bse-tester
Well-known member
Does anyone truly believe that SRM's are the only carriers of prions? If so, I will sell you a bridge in the Nefud Desert for a million bucks. But it is a nice bridge!!
SRM's - Are they the only carrier of Prions??
- Thread starter bse-tester
- Start date
Sandhusker
Well-known member
bse-tester said:
There's a few who were trying to convince me of that last week. Can I get a commission or finder's fee if I send them your way? :lol:
TimH
Well-known member
bse-tester said:
What's the matter bse-tester?? Are you now trying to sell bridges until you can create some demand for your BSE test?? What's next.....used cars?? :roll:
Mike
Well-known member
TimH said:
That's a pretty cheap shot Tim. As evidenced by the Jap position the "Demand" is there. It's just that government agencies are thwarting the attempts of capitalistic thinking companies to meet their customers' demands.
Mike
Well-known member
reader (the Second) said:
I don't know so much about the actual misfolded prions being in the blood. The jury is still out on that one for me.
There has to be a way for those prions or other causatives to travel to the infectious regions (obex, tonsils, spinal cord, etc.) though.
What we don't understand is because these infectious agents are so small beyond belief. We are talking down to the "Atomic Size" levels here.
Check this out:
http://www.rkm.com.au/BSE/
rkaiser
Well-known member
You're going to need motre than a million bucks to prove that Prions are a carrier in the first place bse-tester.
Found in blood - sure, found in muscle tissue - sure, prions are a naturaly occuring type of anti-oxidate. They become a problem when they are overrun with rouge metals and become misfolded. But they are not carriers of anything except for being carriers of heavy metals when injected into unfortunate host animals in bse-testers lab. :wink:
TimH
Well-known member
Mike said:
If you call that a "cheap shot" Mike, what would you call it when someone insinuates that a product, that you produce and make your living from, is somehow unsafe unless you buy and use what he is selling??
Perhaps bse-tester could post some scientific evidence which would answer the question that makes up the title of his post.... he is a scientist isn't he??? Why does he not come right out and say that the "BSE agent", or whatever you want to call it, has been detected in muscle cuts of UTM cattle rather than just implying or suggesting that it has?? ".....I will sell you a bridge...." doesn't sound very scientific to me.
I'm glad you mentioned the "Jap position" Mike. Why did the Japanese drop the mandatory 100% testing requirement but retain the SRM removal requirement?? Why would they continue to remove SRM's from animals that have tested negative for BSE???? Hmmmm???
PS. If I had wanted to take a cheap shot, I would have used "life insurance" instead of "used cars".
Mike
Well-known member
If he were selling E:Coli tests would he be any different?
[/quote]Why did the Japanese drop the mandatory 100% testing requirement but retain the SRM removal requirement?? Why would they continue to remove SRM's from animals that have tested negative for BSE????
TimH
Well-known member
Why did the Japanese drop the mandatory 100% testing requirement but retain the SRM removal requirement?? Why would they continue to remove SRM's from animals that have tested negative for BSE????Mike said:
[/quote]
Japan's prefectures are still testing VOLUNTARILY. Their federal gov't has DROPPED MANDATORY 100% TESTING rules.
Exactly what kind of "economics" would dictate that,in Japan, SRM's are removed from cattle that test negative for BSE?? bse-tester(and others) would have us believe that testing and not SRM removal insures food safety. If this was the case it would seem logical that they would drop the SRM removal and continue with the mandatory 100% testing. Remember, they dropped the testing requirement but retained the SRM removal.
Did Japan re-impose it's import ban on USA beef because it wasn't BSE tested or because a shipment contained SRMs?? :???:
PORKER
Well-known member
Lets test the waste urine that is discharged from the packing houses an see if any pirons show up .Could be interesting!
rkaiser
Well-known member
Go for it Porker, but don't forget to test for metal content as well. :wink:
PORKER
Well-known member
Actually you could test for metals,protiens,disease,and BSE PIRONS.
rkaiser
Well-known member
Capiche?
Prion may be detected but misfolded prions cannot breakdown and pass through places like blood brain barriers.
Prions become misfolded and that is when they become a problem.
The problem with the conventional theory of prions is the difference between the problem misfolded prion and the "antioxidant"(my translation of course) prion which occurs naturally and has a purpose.
I will not argue that prions can be detected and especially misfolded prions. Transmission of misfolded prions Blah Blah Blah
Prion may be detected but misfolded prions cannot breakdown and pass through places like blood brain barriers.
Prions become misfolded and that is when they become a problem.
The problem with the conventional theory of prions is the difference between the problem misfolded prion and the "antioxidant"(my translation of course) prion which occurs naturally and has a purpose.
I will not argue that prions can be detected and especially misfolded prions. Transmission of misfolded prions Blah Blah Blah
bse-tester
Well-known member
First of all, the presence of PrPsc in blood is already a proven fact. The presence of PrPsc in muscle is already a proven fact! The presence of PrPsc throughout the entire body of the "infected" animal is a proven fact. We (our test) detect PrPsc in urine. The urine is the bi-product of blood filtration conducted by the kidney's and thus, we can safely ascertain that the animal - or human - has been subjected to the presence of PrPsc throughout it's entire body and vascular system. It amazes me that some will state that PrPsc is only found in SRM's. That is absolute nonsence! If we are finding PrPsc in urine, blood, muscle and sinue then it stands to reason that it will be found throughout the entire animal as it has been. The fact that PrPsc collects in the brain, the spinal cord and related tissues and also in the lymphatic system is nothing new to science. Secondly - What is new is the political arguments that are driven by economic greed and market share that tend to bring about the smoke and mirror campaigns that are designed to allow for governments to engage in nothing short of criminal activities when they openly state that the meat is safe! This occurred in England and throughout Europe in order to maintain the flow of meat products and the return flow of income to large conglomerates and also the UK Milk industry were loudly endorsing the governments decisions to allow the flow of milk into the UK and European markets, even though they knew that milk might harbor PrPsc, but the levels of contamination we "below" and within acceptable limits. Acceptable to whom??? It is also important to note that the British Government allowed the reccommendations of their government appointed advisory board on the safety and status of British milk, to sway the governments final decisions. It is also important to note that the advisory board was made up of people who came from those companies engaged in the manufacturing and marketing of milk!!! So when I read all this hyped up government rhetoric about PrPsc only being found in SRM's I have to speak out and say that that is nothing short of a bold faced lie spouted by those who know little or nothing about PrPsc and how it affects us and our bovine population.
Lastly, I resent the fact that some on this board feel that all I want to do is push my test to make profit. That is not my goal or the goal of my partners. We are making our test availalbe to all who wish to try it. In fact, we are providing 1000 tests free to anyone who has a lab and wishes to evaluate it. Further to that, I am prepared to offer any lab, anywhere in the world, that has the capability of performing a full scale validation of our test, unlimited access to the test. Any profits made upon our test being accepted for commercial use, will be channeled back into scholarships and research to extend and enhance the scientific understanding of prions and how they affect not only beef but also equally important, people. So please, to those who feel that I am something of a profit-monger - I can assure you I am not. We have already agreed to provide funding to four universities around the world for the further research of prion science and will continue to do so in the future. As for the cost of validation - it is approximately US$350,000 per validation and takes about two years to complete and that comes not out of your pocket my friends, it comes out of mine!!!Frankly, I am tired of some attitudes on this board that seem to think that I am trying to do otherwise. But I did promised my wife that I would play nice in the pool with the rest of the kids so I will say no more on this subject.
Lastly, I resent the fact that some on this board feel that all I want to do is push my test to make profit. That is not my goal or the goal of my partners. We are making our test availalbe to all who wish to try it. In fact, we are providing 1000 tests free to anyone who has a lab and wishes to evaluate it. Further to that, I am prepared to offer any lab, anywhere in the world, that has the capability of performing a full scale validation of our test, unlimited access to the test. Any profits made upon our test being accepted for commercial use, will be channeled back into scholarships and research to extend and enhance the scientific understanding of prions and how they affect not only beef but also equally important, people. So please, to those who feel that I am something of a profit-monger - I can assure you I am not. We have already agreed to provide funding to four universities around the world for the further research of prion science and will continue to do so in the future. As for the cost of validation - it is approximately US$350,000 per validation and takes about two years to complete and that comes not out of your pocket my friends, it comes out of mine!!!Frankly, I am tired of some attitudes on this board that seem to think that I am trying to do otherwise. But I did promised my wife that I would play nice in the pool with the rest of the kids so I will say no more on this subject.
PORKER
Well-known member
BSE tester,Your are my Friend! I have the same dumchoffs trying to cancel out the truth.I just beat my drums a little louder. The fact that PrPsc collects in the brain, the spinal cord and related tissues and also in the lymphatic system is nothing new to science.
What is new is the political arguments that are driven by economic greed and market share that tend to bring about the smoke and mirror campaigns that are designed to allow for governments to engage in nothing short of criminal activities when they openly state that the meat is safe! I AGREE.Just like NCBA and the MIDDLEMEN . All they think what is important is their Pocket book. Your right on to note that the advisory board was made up of people who came from those companies engaged in the manufacturing and marketing of milk!!! So when I read all this hyped up government rhetoric about PrPsc only being found in SRM's I have to speak out and say that that is nothing short of a bold faced lie spouted by those who know little or nothing about PrPsc and how it affects us and our bovine population.
Maybe that I have 30 years left to live is not a big deal ,BUT MY CHILDERN's HEALTH is a BIG DEAL. You GOT MY SUPPORT BSE TESTER!!!!!
What is new is the political arguments that are driven by economic greed and market share that tend to bring about the smoke and mirror campaigns that are designed to allow for governments to engage in nothing short of criminal activities when they openly state that the meat is safe! I AGREE.Just like NCBA and the MIDDLEMEN . All they think what is important is their Pocket book. Your right on to note that the advisory board was made up of people who came from those companies engaged in the manufacturing and marketing of milk!!! So when I read all this hyped up government rhetoric about PrPsc only being found in SRM's I have to speak out and say that that is nothing short of a bold faced lie spouted by those who know little or nothing about PrPsc and how it affects us and our bovine population.
Maybe that I have 30 years left to live is not a big deal ,BUT MY CHILDERN's HEALTH is a BIG DEAL. You GOT MY SUPPORT BSE TESTER!!!!!
rkaiser
Well-known member
A problem all right. You folks want everyone to beleive that prions are found in the all parts of animal bodies. GOOD FOR YOU. Now prove that this misfolded prion can be a danger to human life by crossing the barrier to the brain (IN AN INFECTIOUS WAY) which you all seem to be the area which death comes to the victim.
Where did you make your money bse tester? $350,000.00 per test - Are you into drug smuggling or something? :wink:
Where did you make your money bse tester? $350,000.00 per test - Are you into drug smuggling or something? :wink:
bse-tester
Well-known member
You know, I once thought that you had some interesting things to share on this board but you have shown just how ignorant you really are. Drug smuggling?? Give you pathetic little brain a shake pal. I have worked for 40 years and done well and the fact that I have to answer stupid comments like yours is beyond me, but I find it necessary. The brain barrier as you call it needs to be explained as to precisely what it actually is and I think that you should be the one to explain it - or at least attempt to do so. I am sure you can do it, you speak of it like you know, so put you money where your mouth is Rkaiser and share with us exactly what you think it is!! Then I will tell you how I view it. You talk of it like it is some magic wall around the entire brain that keeps all the ugly bugs out!! So hey, now you have the floor - tell us what exactly it is, in detail please. Put up or shut up. Drug smuggling - Geez man, you have some damn nerve to make a statement like that. You think that all people walk around with the same amount of dollars as you have? Give your head a shake. My partners in the UK have put over 1.5 million pounds into prion research over the last 12 years and we intend to continue to do so. This is not going to go away and the wild accusatory remarks made by people like you makes us want to look for cures for other human ailments also. After you have given us all your rendition and interpretation of what constitutes the detailed description of the so-called "brain barrier" I will make my comments. By the way, the cost of the "test" is only CAN$10.00 to $15.00 per animal and takes only 14-24 hours, but the cost of the VALIDATION OF THE PROTOCOL is US$350.000 and takes two years to complete. Get it right!
rkaiser
Well-known member
The blood brain barrier is the barrier between the brain of some idiot who brags of paying $350,000.00 per validation out of HIS OWN POCKET to help mankind through this BSE issue, and the rest of mankind. :lol: :lol:
Your turn money bags, how do misfolded prions cross the blood brain barrier, or for that matter pass from the gut of a cow to his/her blood muscle tissue, or the infamous SRM?
P.S. - Do cats Fart?
your wasting your time there bse-tester, some dont have a brain, and others just don't know how to use it. watch them try and distort this one;-)
Subject: UK Strategy for Research and Development on Human and Animal Health Aspects of TSEs 2005-2008
Date: February 12, 2006 at 1:08 pm PST
UK Strategy for Research and Development on Human and Animal Health Aspects of Transmissible Spongiform Encephalopathies
2005-2008
snip...
v6.1
Preface
Since the announcement in 1996 of a possible link between BSE in cattle and vCJD in humans two strategy documents for research and development into transmissible spongiform encephalopathies (TSEs) have been produced by the UK government. TSE research has advanced significantly during the past few years, and as senior representatives of the UK public funders of TSE research, we considered it timely to review the current understanding of these diseases and set out a new research strategy that reflected the changes in knowledge.
This document represents the first UK joint human and animal health strategy for TSE research and addresses issues that affect livestock, the food chain and public health. It highlights the improved co-ordination that has taken place between government departments since the publication of the Phillips Report and reflects the overlapping issues of relevance to both human and animal health.
In the production of this document, we have drawn on a wide range of advice from all of the UK's major funders of TSE research and from members of specialist advisory committees such as SEAC, which are detailed within. We have also undertaken wide consultation in the UK and overseas in an attempt to ensure the accuracy of the information included. We are particularly indebted to Professor Chris Bostock (formerly director of the Institute for Animal Health) for his 2004 review of the science, which forms the backbone of this document.
With numbers of BSE cases continuing to fall and vCJD cases apparently stabilising in the UK, it would be easy to be complacent. However, the increasing incidence of chronic wasting disease in the USA reinforces the concern that TSEs are an international problem and one that will need to be monitored carefully for a number of years. In the UK, there remain key issues that continue to pose threats to animal and human health. Not least is the possibility of a non-symptomatic carrier state or the emergence of BSE-like illness in another species such as sheep.
While every attempt is made to reduce exposure to disease it is not always possible to eradicate it completely. Disease management is thus often based on risk assessments of potential exposure and these are based on the latest scientific results.
This document aims to highlight the major scientific uncertainties relating to TSEs and how these will be addressed by the research and development strategies of the major UK funders. The necessary experience of managing BSE and producing scientific evidence upon which to base control policies has led to the development of an extensive UK research base in human and animal health aspects of TSEs.
The UK has a special responsibility to share its expertise in TSEs with Europe and the rest of the world to minimise the effects of TSE infection in other countries.
Although considerable progress has been made, further studies are required to fill in the many gaps in our basic understanding of TSEs and in our knowledge of how TSE epidemics can be effectively controlled. It is therefore vital that the UK research base is maintained and that a co-ordinated and effective funding strategy is adopted for new research. Science develops and inevitably this strategy will require regular reassessment.
3v6.1
Professor Sir John Pattison
Director of Research
Department of Health
Dr John Bell
Chief Executive
Food Standards Agency
Professor Colin Blakemore FRS
Chief Executive
Medical Research Council
Professor Julia Goodfellow CBE
Chief Executive
Biotechnology and Biological Sciences Research Council
Professor Howard Dalton FRS
Chief Scientific Adviser
Department for Environment, Food and Rural Affairs
4v6.1
Executive Summary
1. Transmissible spongiform encephalopathies (TSEs) have been present in human and animal populations for centuries. Interest in them has intensified since BSE became significant in British cattle in the 1990s and especially since its human version became a hazard to the UK population.
2. The number of human fatalities from TSEs in the UK is relatively small, in the low hundreds, and on this criterion TSEs currently appear to present a smaller risk to public health risk than vascular disorders such as heart disease or strokes, which are the UK's biggest killers, or cancers.
3. However, the impact of TSEs has been high and they remain important for a number of reasons. There may be human TSEs with longer latency periods than those that have appeared clinically to date. This could mean a further cost in terms of human life and suffering and to the healthcare system, where considerable resource has already been committed to importing blood products and improving safety measures such as the decontamination of surgical instruments. Identification of another TSE in another species (e.g. BSE in sheep) would affect consumer confidence in British produce, which would add a further burden to a slowly recovering farming and meat industry.
4. The five major UK funders of TSE research each have their own remits, strategies and approaches. The Department of Health and the Department for Environment, Food and Rural Affairs are government departments with responsibility for human and animal health, the environment and the agricultural industry. The Food Standards Agency is a public body established to protect the public from food hazards. The Medical Research Council and the Biotechnology and Biological Sciences Research Council are non-departmental public bodies that fund research in human and animal biology and health.
5. These bodies have different but related interests in TSE research. Although the research councils pay attention to the applicability of the research they fund, they have a strong interest in pursuing excellent science independently of its possible use. The three government departments have responsibilities for human and animal health, and for the environmental and economic ramifications of TSEs, and require sound scientific information on which to base their policies.
6. These organisations are currently (2004/05) spending approximately £35M per year on TSE research. The programmes supported by the five funders are coordinated and discussed with other interested organisations, including devolved UK administrations, the voluntary sector, industry and organisations outside the UK, including the European Commission and research groups in the USA. Central to this cooperation is the TSE R & D Funders Co-ordination Group.
7. Research on TSEs will continue to be necessary in part because of their economic consequences for agriculture, an industry that is already under pressure from a variety of sources. The National Scrapie Plan, which involves eliminating scrapie from the UK sheep flock by removing sheep with lower levels of genetic resistance to it, is costly and requires an adequate base of research knowledge. Furthermore, as a large proportion of the UK population may have been exposed to BSE-contaminated material, the implications for public health and the additional burden on the NHS could be severe. Consequently it is imperative that accurate estimates of the size of the human epidemic are obtained, methods to prevent its spread are continually updated and potential treatments investigated.
5v6.1
8. Research in this area, especially that funded by the research councils, forms part of the general process of advancing knowledge as well as being of practical value. It has been informed by, and in turn informs, advances in our understanding of protein and gene science, and knowledge of human and animal epidemiology. It illuminates important areas of knowledge such as the strength and nature of species barriers and infection processes, including species-to-species and possible mother-to-offspring transmission.
9. Currently, TSEs are one of the rare disease groups where infection leads invariably to death. For this reason, possible treatments are a target for both human and animal TSE research. These might take the form of drug therapy or immunological interventions such as vaccines. If developed for the human population, such interventions would have a high value for patients and their families despite the small number of people affected.
10. TSE research is a growing international field in which the UK has made a significant contribution. The UK is likely to be a valued partner in TSE research for other nations and for international organisations. TSE research has featured in previous European Commission framework programmes for research and is likely to be further funded under the sixth framework programme. The UK is a leader in TSE science and in the cross-agency organisation needed to support the full range of TSE research.
11. The approach to TSE research described in this report includes a number of short-term targets. One of the most pressing is the need for a preclinical diagnostic test for humans and animals. Also important is work on the safety of medical instruments, which is needed by the Department of Health and the UK National Health Service. Other health-related research is directed towards the needs of agencies such as the National Blood Service, which has an interest in blood transfusion hazards. Research is also being pursued on methods for monitoring food for TSE hazards, on animal feed hazards and on animal slaughter practices. This is of interest to Defra and the FSA. Defra has a strong interest in research to support the National Scrapie Plan, to investigate the possibility of BSE in sheep and to establish the risk of TSEs in other farmed animals.
12. The aim of this research is to uncover the science of TSEs, in particular their nature and means of transmission; to develop countermeasures at many points in the food chain; to protect the health of the UK population; and to engage the public in the research and its application.
6v6.1
Introduction
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2.15.3.2 It is difficult to ensure that all cases of vCJD are correctly diagnosed and reported and there is always the worry that some could be missed. Variant CJD occurs in a much younger age group than sporadic CJD68 and it is a concern that cases are perhaps being missed in children and older adults. A survey of over 1,000 children with progressive intellectual and neurological deterioration (PIND), a group that would include vCJD patients, found only previously reported cases of vCJD, indicating that vCJD in children is not being missed68, 314. Although vCJD has been diagnosed in a 74 year old patient315, the possibility remains that cases of vCJD are being missed amongst the elderly. One attempt to estimate the prevalence of infection, as opposed to the incidence of clinical vCJD, is based on a search for the characteristic presence of PrPSc in infected lymphoid tissue in archived specimens of tonsils and appendices removed from patients aged 10 to 50 between 1995 and 1999. The interim findings of this study reported one PrPSc-positive appendix amongst 8318 samples examined, which gives an estimated detectable prevalence of PrPSc accumulation in 120 per million of the population316. However, the finding of a further two PrPSc-positive samples, giving a total of three positive samples in 12 674 samples examined, confirm the wisdom of screening the larger number of samples being collected as part of the National Tonsil Archive333.
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2.2 The prion and other hypotheses
2.2.1 An animal with a TSE infection commonly exhibits an abnormal form (PrPSc or prion) of the cellular prion protein (PrPC). Deposits of PrPSc can take many forms ranging from diffuse widespread distribution to local concentrations of highly ordered aggregates, called amyloid plaques. Deposits of PrPSc can be identified under the microscope in sections of body tissue by selective staining and can be separated from PrPC because PrPSc is insoluble and relatively resistant to protease enzymes used to digest proteins.
2.2.2 The correlation between TSE infection and PrPSc led to the prion hypothesis, that the abnormal form of prion protein is the infectious agent8, 9, 10. Although accepted by many in
19v6.1
the field today, it was highly contentious at first because it went against the then-accepted view that all inherited biological information must be encoded in nucleic acid, DNA or RNA. Alternative hypotheses for the infectious agent include a conventional virus of unknown type11 or a "virino"- an informational molecule, expected to be a small piece of nucleic acid, which is not encoded in the host and which codes for its own replication and binds to the prion protein12.
2.2.3 To date neither a virus nor a virino nucleic acid has been found and most research has focussed on the PrP molecule. Although progress has been made in understanding the structure, function and role in disease of various forms of PrP, the molecular basis of its suggested infectiousness and how it is propagated have not been described. Nor has normal PrP been converted into an infectious form in a test tube in a laboratory, which would provide a formal proof of the hypothesis.
snip...
2.5.4 Many strains of TSEs, even those that have been biologically cloned by repeated passage within a species, can change their characteristics when transmitted from one species to another. This is perhaps not surprising, if the prion hypothesis is correct, given that different species have PrPCs with different amino acid sequences. BSE has been transmitted to a number of different species either "naturally", through contaminated food, as with cats, exotic ruminants, and humans, or experimentally, through injection or feeding, for example sheep, goats and pigs. Each of these species has a different PrPC, but where it has been tested, the strain characteristics of their BSE-derived TSEs are the same as for BSE from cattle. This "stability" of the BSE strain in different PrP backgrounds challenges the notion that shape of PrP in PrPSc encodes the properties of a strain. The shape that, according to the prion hypothesis, defines the BSE strain must be independent of differences, often large, between the amino acid sequence in PrPC. Alternatively, there may be one or more other molecules (yet to be identified) that associate with PrP to determine the strain properties. Knowing the molecular basis of TSE strains is, therefore, at the heart of understanding the nature of the TSE agent.
snip...
3.3.2.4 The prion protein has not been unequivocally shown to be the infectious agent of TSE disease. Although some work is investigating the correlation between PrPSc and infectivity, using transgenic mouse models, this remains a fundamental gap in knowledge. The unequivocal identification of the TSE agent would have a profound effect on the development of appropriate diagnostic tests. For this reason, the search for a non-PrPSc marker for disease is important. Some work is ongoing in the search for alternative markers, using approaches such as metabolomics and proteomics. These approaches search for consistent differences between control and infected animals at several stages of the incubation period. However, an alternative marker for the detection of the disease has not yet been identified. Further characterisation of different conformers of PrP after digestion with proteases and the development and application of other conformation-dependent techniques for detecting PrPSc may allow a better understanding of the significance of atypical results observed in large-scale surveillance studies.
snip...
3.3.3 Prospects for treatment
3.3.3.1 Current strategies involve screening large pharmaceutical libraries to identify possible therapeutic compounds. However, a better understanding of the structures of prion proteins and their biology could lead to a more targeted approach, allowing the design of small molecules which could block abnormal prion protein formation. Approaches underpinning the development of therapeutics remain a priority for the research councils. The identification of a natural mechanism for clearing infectivity from the body could also be exploited for therapeutic purposes.
3.3.3.2 It seems unlikely that a treatment will become available soon to repair damage to the CNS. The research councils fund work on the generic development of stem cell therapy. However, therapies that seek to repair damaged tissue are far in the future and even then would only be of value once infection had been halted. While several strategies to develop a therapeutic are aimed at inhibiting PrPC to PrPSc conversion, success is likely to be improved by the development of good diagnostics to identify individuals with pre-clinical infection.
3.3.3.3 The development and evaluation of a potential therapy is a detailed process that usually takes many years. In addition to continued support for such work, DH and MRC are establishing the infrastructure for rapid clinical evaluation of any agents that have demonstrated anti-prion activity in animals or in vitro. To this end a clinical trial protocol has been developed in conjunction with families and carers through the Medical Research Council's Prion Unit and Clinical Trials Unit, and building capacity for undertaking such work remains a priority.
53
snip...
3.4.0.7 The possibility of an infectious carrier state in apparently healthy animals and humans highlights our limited knowledge of TSE diseases. Work on TSEs may also produce results that have significance for the understanding of other groups of diseases
54v6.1
such as the neurodegenerative changes involved in Alzheimer's and other amyloid brain diseases. A full understanding of TSE transmission is likely to require advances in the understanding of the immune system and will provide insights into aspects of human and animal genetic variability. The Research Councils (BBSRC and MRC) support this underpinning biomedical science.
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3.4.2 The MRC has identified the following key areas in which it would like to continue to receive innovative research proposals:
. The biological and epidemiological relationship between CJD and BSE;
. Epidemiological modelling of CJD;
. The analysis, perception and communication of risk in relation to CJD;
. Early disease progression and diagnosis in life including in vivo imaging approaches, with a focus on the development of non-invasive pre-clinical tests for human TSE diseases, particularly vCJD, e.g. a blood test or throat swab;*
. Integrated molecular, epidemiological and clinical approaches to understanding the cause or causes of sporadic CJD and the relationship with atypical dementias;
. Molecular, genetic, cellular and functional approaches to elucidating mechanisms of TSEs transmission, PrP replication, pathogenesis and clinical progression, with a view to improving understanding of how TSEs cause disease, particularly during the very early stages;*
. The biological function of normal prion protein (PrP);*
. The molecular structure of the prion proteins;*
. Development and improvement of animal models and cell culture systems;*
. Development of approaches to reduce secondary (iatrogenic) infection;*
. Rational approaches to developing therapy including vaccine based treatment approaches.*
* Council has approved programmes of work within these areas at the MRC Prion Unit
55
http://www.mrc.ac.uk/pdf-about-tse_uk_strategy_june2005.pdf
Coexistence of multiple PrPSc types in individuals with
Creutzfeldt-Jakob disease
Magdalini Polymenidou, Katharina Stoeck, Markus
Glatzel, Martin Vey, Anne Bellon, and Adriano Aguzzi
Summary
Background The molecular typing of sporadic
Creutzfeldt-Jakob disease (CJD) is based on the size
and glycoform
ratio of protease-resistant prion protein (PrPSc), and
on PRNP haplotype. On digestion with proteinase K, type
1 and
type 2 PrPSc display unglycosylated core fragments of
21 kDa and 19 kDa, resulting from cleavage around amino
acids 82 and 97, respectively.
Methods We generated anti-PrP monoclonal antibodies to
epitopes immediately preceding the differential proteinase
K cleavage sites. These antibodies, which were
designated POM2 and POM12, recognise type 1, but not
type 2, PrPSc.
Findings We studied 114 brain samples from 70 patients
with sporadic CJD and three patients with variant CJD.
Every patient classified as CJD type 2, and all variant
CJD patients, showed POM2/POM12 reactivity in the
cerebellum and other PrPSc-rich brain areas, with a
typical PrPSc type 1 migration pattern.
Interpretation The regular coexistence of multiple
PrPSc types in patients with CJD casts doubts on the
validity of
electrophoretic PrPSc mobilities as surrogates for
prion strains, and questions the rational basis of
current CJD
classifications.
snip...
The above results set the existing CJD classifications
into debate and introduce interesting questions about
human CJD types. For example, do human prion types
exist in a dynamic equilibrium in the brains of affected
individuals? Do they coexist in most or even all CJD
cases? Is the biochemically identified PrPSc type simply
the dominant type, and not the only PrPSc species?
Published online October 31, 2005
http://neurology.thelancet.com
Detection of Type 1 Prion Protein in Variant
Creutzfeldt-Jakob Disease
Helen M. Yull,* Diane L. Ritchie,*
Jan P.M. Langeveld,? Fred G. van Zijderveld,?
Moira E. Bruce,? James W. Ironside,* and
Mark W. Head*
From the National CJD Surveillance Unit,* School of
Molecular
and Clinical Medicine, University of Edinburgh, Edinburgh,
United Kingdom; Central Institute for Animal Disease
Control
(CIDC)-Lelystad, ? Lelystad, The Netherlands; Institute
for Animal
Health, Neuropathogenesis Unit, ? Edinburgh, United Kingdom
Molecular typing of the abnormal form of the prion
protein (PrPSc) has come to be regarded as a powerful
tool in the investigation of the prion diseases. All
evidence
thus far presented indicates a single PrPSc molecular
type in variant Creutzfeldt-Jakob disease (termed
type 2B), presumably resulting from infection with a
single strain of the agent (bovine spongiform
encephalopathy).
Here we show for the first time that the PrPSc
that accumulates in the brain in variant Creutzfeldt-
Jakob disease also contains a minority type 1 component.
This minority type 1 PrPSc was found in all 21
cases of variant Creutzfeldt-Jakob disease tested,
irrespective
of brain region examined, and was also
present in the variant Creutzfeldt-Jakob disease tonsil.
The quantitative balance between PrPSc types was maintained
when variant Creutzfeldt-Jakob disease was
transmitted to wild-type mice and was also found in
bovine spongiform encephalopathy cattle brain, indicating
that the agent rather than the host specifies their
relative representation. These results indicate that PrPSc
molecular typing is based on quantitative rather than
qualitative phenomena and point to a complex relationship
between prion protein biochemistry, disease phenotype
and agent strain. (Am J Pathol 2006, 168:151-157;
DOI: 10.2353/ajpath.2006.050766)
snip...
Discussion
In the apparent absence of a foreign nucleic acid genome
associated with the agents responsible for transmissible
spongiform encephalopathies or prion diseases,
efforts to provide a molecular definition of agent strain
have focused on biochemical differences in the abnormal,
disease-associated form of the prion protein, termed
PrPSc. Differences in PrPSc conformation and glycosylation
have been proposed to underlie disease phenotype
and form the biochemical basis of agent strain. This
proposal has found support in the observation that the
major phenotypic subtypes of sCJD appear to correlate
with the presence of either type 1 or type 2 PrPSc in
combination with the presence of either methionine or
valine at codon 129 of the prion protein gene.2 Similarly,
the PrPSc type associated with vCJD correlates with the
presence of type 2 PrPSc and is distinct from that found in
sCJD because of a characteristically high occupancy of
both N-linked glycosylation sites (type 2B).6,11 The
means by which such conformational difference is detected
is somewhat indirect; relying on the action of proteases,
primarily proteinase K, to degrade the normal
Figure 6. Type 1 PrPSc is a stable minority component
of PrPSc from the vCJD
brain. Western blot analysis of PrP in a sample of
cerebral cortex from a
case
of vCJD during digestion with proteinase K is shown.
Time points assayed
are indicated in minutes (T0, 5, 10, 30, 60, 120, 180).
Duplicate blots were
probed with 3F4, which detects both type 1 and type 2
PrPSc, and with 12B2,
which detects type 1. The insert shows a shorter
exposure of the same time
course study from a separate experiment also probed
with 3F4. Both blots
included samples of cerebral cortex from a case of
sporadic CJD MM1 (Type
1) and molecular weight markers (Markers) indicate
weights in kd.
Figure 7. A minority type 1-like PrPSc is found in vCJD
tonsil, vCJD
transmitted
to mice and in BSE. Western blot analysis of PrPSc in a
concentrated
sample of tonsil from a case of vCJD (Tonsil), in a
concentrated brain
sample
of a wild-type mouse (C57BL) infected with vCJD and in
a sample of cattle
BSE brain (BSE) is shown. Tissue extracts were digested
with proteinase K.
Duplicate blots were probed with either 3F4 or 6H4,
both of which detect
type 1 and type 2 PrPSc, and with 12B2, which detects
type 1. The blots
included samples of cerebral cortex from a case of
sporadic CJD MM1 (Type
1) and molecular weight markers (Markers) indicate
weights in kd.
Type 1 PrPSc in Variant Creutzfeldt-Jakob Disease 155
AJP January 2006, Vol. 168, No. 1
cellular form of PrP and produce a protease-resistant
core fragment of PrPSc that differs in the extent of its
N-terminal truncation according to the original
conformation.
A complication has recently arisen with the finding that
both type 1 and type 2 can co-exist in the brains of
patients with sCJD.2,5-8 More recently this same phenomenon
has been demonstrated in patients with iatrogenically
acquired and familial forms of human prion disease.
9,10 The existence of this phenomenon is now
beyond doubt but its prevalence and its biological
significance
remain a matter of debate.
Conventional Western blot analysis using antibodies
that detect type 1 and type 2 PrPSc has severe quantitative
limitations for the co-detection of type 1 and type 2
PrPSc in individual samples, suggesting that the prevalence
of co-occurrence of the two types might be underestimated.
We have sought to circumvent this problem by
using an antibody that is type 1-specific and applied this
to the sole remaining human prion disease where the
phenomenon of mixed PrPSc types has not yet been
shown, namely vCJD.
These results show that even in vCJD where susceptible
individuals have been infected supposedly by a
single strain of agent, both PrPSc types co-exist: a
situation
reminiscent of that seen when similarly discriminant
antibodies were used to analyze experimental BSE in
sheep.14,17 In sporadic and familial CJD, individual
brains can show a wide range of relative amounts of the
two types in samples from different regions, but where
brains have been thoroughly investigated a predominant
type is usually evident.2,6,10 This differs from this
report
on vCJD, where type 1 is present in all samples
investigated
but always as a minor component that never
reaches a level at which it is detectable without a type
1-specific antibody. It would appear that the relative
balance
between type 1 and type 2 is controlled within
certain limits in the vCJD brain. A minority type-1-like
band is also detected by 12B2 in vCJD tonsil, in BSE
brain and in the brains of mice experimentally infected
with vCJD, suggesting that this balance of types is agent,
rather than host or tissue, specific. Interestingly the
"glycoform
signature" of the type 2 PrPSc found in vCJD (type
2B) is also seen in the type 1 PrPSc components, suggesting
that it could legitimately be termed type 1B.
PrPSc isotype analysis has proven to be extremely
useful in the differential diagnosis of CJD and is
likely to
continue to have a major role in the investigation of human
prion diseases. However, it is clear, on the basis of
these findings, that molecular typing has quantitative
limitations
and that any mechanistic explanation of prion
replication and the molecular basis of agent strain
variation
must accommodate the co-existence of multiple
prion protein conformers. Whether or not the different
conformers we describe here correlate in a simple and
direct way with agent strain remains to be determined. In
principle two interpretations present themselves: either
the two conformers can be produced by a single strain of
agent or vCJD (and, therefore, presumably BSE) results
from a mixture of strains, one of which generally
predominates.
Evidence for the isolation in mice of more than one
strain from individual isolates of BSE has been presented
previously.18,19
One practical consequence of our findings is that the
correct interpretation of transmission studies will depend
on a full examination of the balance of molecular types
present in the inoculum used to transmit disease, in
addition
to a thorough analysis of the molecular types that
arise in the recipients. Another consequence relates to
the diagnostic certainty of relying on PrPSc molecular
type alone when considering the possibility of BSE
infection
or secondary transmission in humans who have a
genotype other than methionine at codon 129 of the
PRNP gene. In this context it is interesting to note
that this
minority type 1B component resembles the type 5 PrPSc
described previously to characterize vCJD transmission
into certain humanized PRNP129VV transgenic mouse
models.12,20 This apparently abrupt change in molecular
phenotype might represent a selection process imposed
by this particular transgenic mouse model. Irrespective of
whether this proves to be the case, the results shown
here point to further complexities in the relationship
between
the physico-chemical properties of the prion protein,
human disease phenotype, and prion agent strain.
Acknowledgments
snip...
Type 1 PrPSc in Variant Creutzfeldt-Jakob Disease 157
AJP January 2006, Vol. 168, No. 1 ...TSS
http://ajp.amjpathol.org/cgi/content/abstract/168/1/151maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=prion&searchid=1136646133963_237&FIRSTINDEX=0&volume=168&issue=1&journalcode=amjpathol
Neuropathology and Applied Neurobiology
(2005),
31
, 565-579 doi: 10.1111/j.1365-2990.2005.00697.x
© 2005 Blackwell Publishing Ltd
565
Blackwell Science, LtdOxford, UKNANNeuropathology and
Applied Neurobiology0305-1846Blackwell Publishing Ltd, 2005
316565579
Review article
Phenotypic variability in human prion diseases
J. W. Ironside, D. L. Ritchie and M. W. Head
National Creutzfeldt-Jakob Disease Surveillance Unit,
Division of Pathology, University of Edinburgh,
Edinburgh, UK
J. W. Ironside, D. L. Ritchie and M. W. Head (2005)
Neuropathology and Applied Neurobiology
31,
565-579
Phenotypic variability in human prion diseases
Human prion diseases are rare neurodegenerative disorders
that can occur as sporadic, familial or acquired disorders.
Within each of these categories there is a wide range
of phenotypic variation that is not encountered in other
neurodegenerative disorders. The identification of the
prion protein and its key role in the pathogenesis of this
diverse group of diseases has allowed a fuller
understanding
of factors that influence disease phenotype. In particular,
the naturally occurring polymorphism at codon 129
in the prion protein gene has a major influence on the
disease
phenotype in sporadic, familial and acquired prion
diseases, although the underlying mechanisms remain
unclear. Recent technical advances have improved our
ability to study the isoforms of the abnormal prion protein
in the brain and in other tissues. This has lead to the
concept
of molecular strain typing, in which different isoforms
of the prion protein are proposed to correspond to
individual strains of the transmissible agent, each with
specific biological properties. In sporadic
Creutzfeldt-Jakob
disease there are at least six major combinations of codon
129 genotype and prion protein isotype, which appear to
relate to distinctive clinical subgroups of this disease.
However, these relationships are proving to be more complex
than first considered, particularly in cases with more
than a single prion protein isotype in the brain. Further
work is required to clarify these relationships and to
explain the mechanism of neuropathological targeting of
specific brain regions, which accounts for the diversity of
clinical features within human prion diseases.
© 2005 Blackwell Publishing Ltd, Neuropathology and
Applied Neurobiology, 31, 565-579
===================================
BSE prions propagate as either variant CJD-like or
sporadic CJD-like prion strains in transgenic mice
expressing human prion protein
The EMBO Journal Vol. 21 No. 23 pp. 6358±6366, 2002
Emmanuel A.Asante, Jacqueline M.Linehan,
Melanie Desbruslais, Susan Joiner,
Ian Gowland, Andrew L.Wood, Julie Welch,
Andrew F.Hill, Sarah E.Lloyd,
Jonathan D.F.Wadsworth and
John Collinge1
MRC Prion Unit and Department of Neurodegenerative Disease,
Institute of Neurology, University College, Queen Square,
London WC1N 3BG, UK
1Corresponding author
e-mail: j.collinge@prion.ucl.ac.uk.
Variant Creutzfeldt±Jakob disease (vCJD) has been
recognized to date only in individuals homozygous for
methionine at PRNP codon 129. Here we show that
transgenic mice expressing human PrP methionine
129, inoculated with either bovine spongiform
encephalopathy (BSE) or variant CJD prions, may
develop the neuropathological and molecular phenotype
of vCJD, consistent with these diseases being
caused by the same prion strain. Surprisingly, however,
BSE transmission to these transgenic mice, in
addition to producing a vCJD-like phenotype, can also
result in a distinct molecular phenotype that is
indistinguishable
from that of sporadic CJD with PrPSc
type 2. These data suggest that more than one BSEderived
prion strain might infect humans; it is therefore
possible that some patients with a phenotype consistent
with sporadic CJD may have a disease arising
from BSE exposure.
snip...
These studies further strengthen the evidence that vCJD
is caused by a BSE-like prion strain. Also, remarkably, the
key neuropathological hallmark of vCJD, the presence of
abundant ¯orid PrP plaques, can be recapitulated on BSE
or vCJD transmission to these mice. However, the most
surprising aspect of the studies was the ®nding that an
alternate pattern of disease can be induced in 129MM
Tg35 mice from primary transmission of BSE, with a
molecular phenotype indistinguishable from that of a
subtype
of sporadic CJD. This ®nding has important potential
implications as it raises the possibility that some humans
infected with BSE prions may develop a clinical disease
indistinguishable from classical CJD associated with type 2
PrPSc. This is, in our experience, the commonest molecular
sub-type of sporadic CJD. In this regard, it is of interest
that the reported incidence of sporadic CJD has risen
in the
UK since the 1970s (Cousens et al., 1997). This has been
attributed to improved case ascertainment, particularly as
much of the rise is reported from elderly patients and
similar rises in incidence were noted in other European
countries without reported BSE (Will et al., 1998).
However, it is now clear that BSE is present in many
European countries, albeit at a much lower incidence than
was seen in the UK. While improved ascertainment is
likely to be a major factor in this rise, that some of
these
additional cases may be related to BSE exposure cannot be
ruled out. It is of interest in this regard that a 2-fold
increase in the reported incidence of sporadic CJD in 2001
has recently been reported for Switzerland, a country that
had the highest incidence of cattle BSE in continental
Europe between 1990 and 2002 (Glatzel et al., 2002). No
epidemiological case±control studies with strati®cation of
CJD cases by molecular sub-type have yet been reported.
It will be important to review the incidence of sporadic
CJD associated with PrPSc type 2 and other molecular
subtypes
in both BSE-affected and unaffected countries in the
light of these ®ndings. If human BSE prion infection can
result in propagation of type 2 PrPSc, it would be expected
that such cases would be indistinguishable on clinical,
pathological and molecular criteria from classical CJD. It
may also be expected that such prions would behave
biologically like those isolated from humans with sporadic
CJD with type 2 PrPSc. The transmission properties of
prions associated with type 2 PrPSc from BSE-inoculated
129MM Tg35 mice are being investigated by serial
passage.
We consider these data inconsistent with contamination
of some of the 129MM Tg35 mice with sporadic CJD
prions. These transmission studies were performed according
to rigorous biosafety protocols for preparation of
inocula and both the inoculation and care of mice, which
are all uniquely identi®ed by sub-cutaneous transponders.
However, crucially, the same BSE inocula have been used
on 129VV Tg152 and 129MM Tg45 mice, which are
highly sensitive to sporadic CJD but in which such
transmissions producing type 2 PrPSc were not observed.
Furthermore, in an independent experiment, separate
inbred lines of wild-type mice, which are highly resistant
to sporadic CJD prions, also propagated two distinctive
PrPSc types on challenge with either BSE or vCJD. No
evidence of spontaneous prion disease or PrPSc has been
seen in groups of uninoculated or mock-inoculated aged
129MM Tg35 mice.
While distinctive prion isolates have been derived from
BSE passage in mice previously (designated 301C and
301V), these, in contrast to the data presented here, are
propagated in mice expressing different prion proteins
(Bruce et al., 1994). It is unclear whether our ®ndings
indicate the existence of more than one prion strain in
individual cattle with BSE, with selection and preferential
replication of distinct strains by different hosts, or that
`mutation' of a unitary BSE strain occurs in some types of
host. Western blot analysis of single BSE isolates has not
shown evidence of the presence of a proportion of
monoglycosylated dominant PrPSc type in addition to the
diglycosylated dominant pattern (data not shown).
Extensive strain typing of large numbers of individual
BSE-infected cattle either by biological or molecular
methods has not been reported.
Presumably, the different genetic background of the
different inbred mouse lines is crucial in determining
which prion strain propagates on BSE inoculation. The
transgenic mice described here have a mixed genetic
background with contributions from FVB/N, C57BL/6 and
129Sv inbred lines; each mouse will therefore have a
different genetic background. This may explain the
differing response of individual 129MM Tg35 mice, and
the difference between 129MM Tg35 and 129MM Tg45
mice, which are, like all transgenic lines, populations
derived from single founders. Indeed, the consistent
distinctive strain propagation in FVB and C57BL/6 versus
SJL and RIIIS lines may allow mapping of genes relevant
to strain selection and propagation, and these studies
are in
progress.
That different prion strains can be consistently isolated
in different inbred mouse lines challenged with BSE
prions argues that other species exposed to BSE may
develop prion diseases that are not recognizable as being
caused by the BSE strain by either biological or molecular
strain typing methods. As with 129MM Tg35 mice, the
prions replicating in such transmissions may be
indistinguishable
from naturally occurring prion strains. It
remains of considerable concern whether BSE has transmitted
to, and is being maintained in, European sheep
¯ocks. Given the diversity of sheep breeds affected by
scrapie, it has to be considered that some sheep might have
become infected with BSE, but propagated a distinctive
strain type indistinguishable from those of natural sheep
scrapie. ...
The EMBO Journal Vol. 21 No. 23 pp. 6358±6366, 2002
6358 ãEuropean Molecular Biology Organization
http://embojournal.npgjournals.com/cgi/reprint/21/23/6358
J Neuropsychiatry Clin Neurosci 17:489-495, November 2005
doi: 10.1176/appi.neuropsych.17.4.489
© 2005 American Psychiatric Publishing, Inc.
Psychiatric Manifestations of Creutzfeldt-Jakob
Disease: A 25-Year Analysis
Christopher A. Wall, M.D., Teresa A. Rummans, M.D.,
Allen J. Aksamit, M.D.,
Lois E. Krahn, M.D. and V. Shane Pankratz, Ph.D.
Received April 20, 2004; revised September 9, 2004;
accepted September 13,
2004. From the Mayo Clinic, Department of Psychiatry
and Psychology,
Rochester, Minnesota; Mayo Clinic, Department of
Neurology, Rochester,
Minnesota. Address correspondence to Dr. Wall, Mayo
Clinic, Department of
Psychiatry and Psychology, Mayo Building-W11A, 200
First St., SW, Rochester,
MN 55905; wall.chris@mayo.edu. (E-mail).
This study characterizes the type and timing of
psychiatric manifestations
in sporadic Creutzfeldt-Jakob disease (sCJD).
Historically, sCJD has been
characterized by prominent neurological symptoms, while
the variant form
(vCJD) is described as primarily psychiatric in
presentation and course: A
retrospective review of 126 sCJD patients evaluated at
the Mayo Clinic from
1976-2001 was conducted. Cases were reviewed for
symptoms of depression,
anxiety, psychosis, behavior dyscontrol, sleep
disturbances, and
neurological signs during the disease course. Eighty
percent of the cases
demonstrated psychiatric symptoms within the first 100
days of illness, with
26% occurring at presentation. The most commonly
reported symptoms in this
population included sleep disturbances, psychotic
symptoms, and depression.
Psychiatric manifestations are an early and prominent
feature of sporadic
CJD, often occurring prior to formal diagnosis.
snip...
CONCLUSIONS
Historically, psychiatric manifestations have been
described as a relatively
infrequent occurrence in the sporadic form of
creutzfeldt-Jakob disease.
However, our findings suggest otherwise. In this study,
a vast majority of
the cases were noted to have at least one psychiatric
symptom during the
course of illness, with nearly one-quarter occurring in
the prodromal or
presenting phase of the illness. After comparing the
frequency of
neuropsychiatric symptoms in sporadic CJD to studies
describing the variant
form of CJD, we found that there are fewer clinical
differences than
previously reported.5-7 While the age of patients
with vCJD presentation
is significantly younger and the course of illness is
longer, the type and
timing of psychiatric manifestations appear similar
between these two
diseases. ...snip...
http://neuro.psychiatryonline.org/cgi/content/abstract/17/4/489
Personal Communication
-------- Original Message --------
Subject: re-BSE prions propagate as
either variant CJD-like or sporadic CJD Date: Thu, 28
Nov 2002 10:23:43
-0000 From: "Asante, Emmanuel A" To:
"'flounder@wt.net'"
Dear Terry,
I have been asked by Professor Collinge to respond to
your request. I am
a Senior Scientist in the MRC Prion Unit and the lead
author on the
paper. I have attached a pdf copy of the paper for your
attention. Thank
you for your interest in the paper.
In respect of your first question, the simple answer
is, yes. As you
will find in the paper, we have managed to associate
the alternate
phenotype to type 2 PrPSc, the commonest sporadic CJD.
It is too early to be able to claim any further
sub-classification in
respect of Heidenhain variant CJD or Vicky Rimmer's
version. It will
take further studies, which are on-going, to establish
if there are
sub-types to our initial finding which we are now
reporting. The main
point of the paper is that, as well as leading to the
expected new
variant CJD phenotype, BSE transmission to the
129-methionine genotype
can lead to an alternate phenotype which is
indistinguishable from type
2 PrPSc.
I hope reading the paper will enlighten you more on the
subject. If I
can be of any further assistance please to not hesitate
to ask. Best wishes.
Emmanuel Asante
<> ____________________________________
Dr. Emmanuel A Asante MRC Prion Unit & Neurogenetics
Dept. Imperial
College School of Medicine (St. Mary's) Norfolk Place,
LONDON W2 1PG
Tel: +44 (0)20 7594 3794 Fax: +44 (0)20 7706 3272 email:
e.asante@ic.ac.uk. (until 9/12/02)
New e-mail: e.asante@prion.ucl.ac.uk. (active from now)
____________________________________
Human Prion Protein with
Valine 129 Prevents Expression
of Variant CJD Phenotype
Jonathan D. F. Wadsworth, Emmanuel A. Asante,
Melanie Desbruslais, Jacqueline M. Linehan, Susan Joiner,
Ian Gowland, Julie Welch, Lisa Stone, Sarah E. Lloyd,
Andrew F. Hill,* Sebastian Brandner, John Collinge.
Variant Creutzfeldt-Jakob disease (vCJD) is a unique
and highly distinctive
clinicopathological and molecular phenotype of human
prion disease
associated with infection with bovine spongiform
encephalopathy (BSE)-like
prions. Here, we found that generation of this
phenotype in transgenic mice
required expression of human prion protein (PrP) with
methionine 129.
Expression of human PrP with valine 129 resulted in a
distinct phenotype and,
remarkably, persistence of a barrier to transmission of
BSE-derived prions on
subpassage. Polymorphic residue 129 of human PrP
dictated propagation of
distinct prion strains after BSE prion infection. Thus,
primary and secondary
human infection with BSE-derived prions may result in
sporadic CJD-like or
novel phenotypes in addition to vCJD, depending on the
genotype of the prion
source and the recipient.
snip...
3 DECEMBER 2004 VOL 306 SCIENCE
http://www.sciencemag.org
Characterization of two distinct prion strains
derived from bovine spongiform encephalopathy
transmissions to inbred mice
Sarah E. Lloyd, Jacqueline M. Linehan, Melanie Desbruslais,
Susan Joiner, Jennifer Buckell, Sebastian Brandner,
Jonathan D. F. Wadsworth and John Collinge
Correspondence
John Collinge
j.collinge@prion.ucl.ac.uk.
MRC Prion Unit and Department of Neurodegenerative
Disease, Institute of Neurology,
University College, London WC1N 3BG, UK
Received 9 December 2003
Accepted 27 April 2004
Distinct prion strains can be distinguished by
differences in incubation period, neuropathology
and biochemical properties of disease-associated prion
protein (PrPSc) in inoculated mice.
Reliable comparisons of mouse prion strain properties
can only be achieved after passage in
genetically identical mice, as host prion protein
sequence and genetic background are known
to modulate prion disease phenotypes. While multiple
prion strains have been identified in
sheep scrapie and Creutzfeldt-Jakob disease, bovine
spongiform encephalopathy (BSE) is
thought to be caused by a single prion strain. Primary
passage of BSE prions to different lines
of inbred mice resulted in the propagation of two
distinct PrPSc types, suggesting that two
prion strains may have been isolated. To investigate
this further, these isolates were
subpassaged in a single line of inbred mice (SJL) and
it was confirmed that two distinct prion
strains had been identified. MRC1 was characterized by
a short incubation time (110±3 days),
a mono-glycosylated-dominant PrPSc type and a
generalized diffuse pattern of PrP-immunoreactive
deposits, while MRC2 displayed a much longer incubation
time (155±1 days),
a di-glycosylated-dominant PrPSc type and a distinct
pattern of PrP-immunoreactive deposits
and neuronal loss. These data indicate a crucial
involvement of the host genome in modulating
prion strain selection and propagation in mice. It is
possible that multiple disease phenotypes
may also be possible in BSE prion infection in humans
and other animals.
snip...
Journal of General Virology (2004), 85, 2471-2478 DOI
10.1099/vir.0.79889-0
http://vir.sgmjournals.org/cgi/content/abstract/85/8/2471
Medical Sciences
Identification of a second bovine amyloidotic
spongiform encephalopathy: Molecular similarities with
sporadic Creutzfeldt-Jakob disease
Cristina Casalone *, Gianluigi Zanusso , Pierluigi
Acutis *, Sergio Ferrari , Lorenzo Capucci , Fabrizio
Tagliavini ¶, Salvatore Monaco ||, and Maria Caramelli *
*Centro di Referenza Nazionale per le Encefalopatie
Animali, Istituto Zooprofilattico Sperimentale del
Piemonte, Liguria e Valle d'Aosta, Via Bologna, 148,
10195 Turin, Italy; Department of Neurological and
Visual Science, Section of Clinical Neurology,
Policlinico G.B. Rossi, Piazzale L.A. Scuro, 10, 37134
Verona, Italy; Istituto Zooprofilattico Sperimentale
della Lombardia ed Emilia Romagna, Via Bianchi, 9,
25124 Brescia, Italy; and ¶Istituto Nazionale
Neurologico "Carlo Besta," Via Celoria 11, 20133 Milan,
Italy
Edited by Stanley B. Prusiner, University of
California, San Francisco, CA, and approved December
23, 2003 (received for review September 9, 2003)
Transmissible spongiform encephalopathies (TSEs), or
prion diseases, are mammalian neurodegenerative
disorders characterized by a posttranslational
conversion and brain accumulation of an insoluble,
protease-resistant isoform (PrPSc) of the host-encoded
cellular prion protein (PrPC). Human and animal TSE
agents exist as different phenotypes that can be
biochemically differentiated on the basis of the
molecular mass of the protease-resistant PrPSc
fragments and the degree of glycosylation.
Epidemiological, molecular, and transmission studies
strongly suggest that the single strain of agent
responsible for bovine spongiform encephalopathy (BSE)
has infected humans, causing variant Creutzfeldt-Jakob
disease. The unprecedented biological properties of the
BSE agent, which circumvents the so-called "species
barrier" between cattle and humans and adapts to
different mammalian species, has raised considerable
concern for human health. To date, it is unknown
whether more than one strain might be responsible for
cattle TSE or whether the BSE agent undergoes
phenotypic variation after natural transmission. Here
we provide evidence of a second cattle TSE. The
disorder was pathologically characterized by the
presence of PrP-immunopositive amyloid plaques, as
opposed to the lack of amyloid deposition in typical
BSE cases, and by a different pattern of regional
distribution and topology of brain PrPSc accumulation.
In addition, Western blot analysis showed a PrPSc type
with predominance of the low molecular mass glycoform
and a protease-resistant fragment of lower molecular
mass than BSE-PrPSc. Strikingly, the molecular
signature of this previously undescribed bovine PrPSc
was similar to that encountered in a distinct subtype
of sporadic Creutzfeldt-Jakob disease.
--------------------------------------------------------------------------------
C.C. and G.Z. contributed equally to this work.
||To whom correspondence should be addressed.
E-mail: salvatore.monaco@mail.univr.it. .
www.pnas.org/cgi/doi/10.1073/pnas.0305777101
snip...
Phenotypic Similarities Between BASE and sCJD. The
transmissibility
of CJD brains was initially demonstrated in primates
(27), and
classification of atypical cases as CJD was based on
this property
(28). To date, no systematic studies of strain typing
in sCJD have
been provided, and classification of different subtypes
is based
on clinical, neuropathological, and molecular features
(the polymorphic
PRNP codon 129 and the PrPSc glycotype) (8, 9, 15, 19).
The importance of molecular PrPSc characterization in
assessing
the identity of TSE strains is underscored by several
studies,
showing that the stability of given disease-specific
PrPSc types is
maintained upon experimental propagation of sCJD, familial
CJD, and vCJD isolates in transgenic PrP-humanized mice (8,
29). Similarly, biochemical properties of BSE- and
vCJDassociated
PrPSc molecules remain stable after passage to mice
expressing bovine PrP (30). Recently, however, it has been
reported that PrP-humanized mice inoculated with BSE
tissues
may also propagate a distinctive PrPSc type, with a
''monoglycosylated-
dominant'' pattern and electrophoretic mobility of the
unglycosylated fragment slower than that of vCJD and
BSE (31).
Strikingly, this PrPSc type shares its molecular
properties with the
a PrPSc molecule found in classical sCJD. This
observation is at
variance with the PrPSc type found in MV2 sCJD cases and in
cattle BASE, showing a monoglycosylated-dominant
pattern but
faster electrophoretic mobility of the
protease-resistant fragment
as compared with BSE. In addition to molecular properties
of PrPSc, BASE and MV2 sCJD share a distinctive pattern of
intracerebral PrP deposition, which occurs as
plaque-like and
amyloid-kuru plaques. Differences were, however,
observed in
the regional distribution of PrPSc. While inMV2 sCJD
cases the
largest amounts of PrPSc were detected in the cerebellum,
brainstem, and striatum, in cattle BASE these areas
were less
involved and the highest levels of PrPSc were recovered
from the
thalamus and olfactory regions.
In conclusion, decoding the biochemical PrPSc signature of
individual human and animal TSE strains may allow the
identification
of potential risk factors for human disorders with
unknown etiology, such as sCJD. However, although BASE and
sCJD share several characteristics, caution is dictated
in assessing
a link between conditions affecting two different mammalian
species, based on convergent biochemical properties of
diseaseassociated
PrPSc types. Strains of TSE agents may be better
characterized upon passage to transgenic mice. In the
interim
until this is accomplished, our present findings
suggest a strict
epidemiological surveillance of cattle TSE and sCJD
based on
molecular criteria.
http://www.pnas.org/cgi/reprint/0305777101v1
Published online before print March 20, 2001,
10.1073/pnas.041490898
Neurobiology
Adaptation of the bovine spongiform encephalopathy
agent to primates and comparison with Creutzfeldt-
Jakob disease: Implications for human health
Corinne Ida Lasmézas*,, Jean-Guy Fournier*, Virginie
Nouvel*, Hermann Boe*, Domíníque Marcé*, François
Lamoury*, Nicolas Kopp, Jean-Jacques Hauw§, James
Ironside¶, Moira Bruce, Dominique Dormont*, and
Jean-Philippe Deslys*
* Commissariat à l'Energie Atomique, Service de
Neurovirologie, Direction des Sciences du
Vivant/Département de Recherche Medicale, Centre de
Recherches du Service de Santé des Armées 60-68, Avenue
du Général Leclerc, BP 6, 92 265 Fontenay-aux-Roses
Cedex, France; Hôpital Neurologique Pierre Wertheimer,
59, Boulevard Pinel, 69003 Lyon, France; § Laboratoire
de Neuropathologie, Hôpital de la Salpêtrière, 83,
Boulevard de l'Hôpital, 75013 Paris, France; ¶
Creutzfeldt-Jakob Disease Surveillance Unit, Western
General Hospital, Crewe Road, Edinburgh EH4 2XU, United
Kingdom; and Institute for Animal Health,
Neuropathogenesis Unit, West Mains Road, Edinburgh EH9
3JF, United Kingdom
Edited by D. Carleton Gajdusek, Centre National de la
Recherche Scientifique, Gif-sur-Yvette, France, and
approved December 7, 2000 (received for review October
16, 2000)
Abstract
There is substantial scientific evidence to support the
notion that bovine spongiform encephalopathy (BSE) has
contaminated human beings, causing variant
Creutzfeldt-Jakob disease (vCJD). This disease has
raised concerns about the possibility of an iatrogenic
secondary transmission to humans, because the
biological properties of the primate-adapted BSE agent
are unknown. We show that (i) BSE can be transmitted
from primate to primate by intravenous route in 25
months, and (ii) an iatrogenic transmission of vCJD to
humans could be readily recognized pathologically,
whether it occurs by the central or peripheral route.
Strain typing in mice demonstrates that the BSE agent
adapts to macaques in the same way as it does to humans
and confirms that the BSE agent is responsible for vCJD
not only in the United Kingdom but also in France. The
agent responsible for French iatrogenic growth
hormone-linked CJD taken as a control is very different
from vCJD but is similar to that found in one case of
sporadic CJD and one sheep scrapie isolate. These data
will be key in identifying the origin of human cases of
prion disease, including accidental vCJD transmission,
and could provide bases for vCJD risk assessment.
snip...
Characterization of the CJD and Scrapie Strains.
Controls were set up by transmitting one French and one
U.S. scrapie isolate from ruminants as well as French
sCJD and iCJD cases from humans. None of these revealed
a lesion profile or transmission characteristics
similar or close to those of BSE or vCJD, respectively,
thus extending to the present French scrapie isolate
the previous observation that the BSE agent was
different from all known natural scrapie strains (4, 24).
The lesion profiles of sCJD and iCJD differed only
slightly in severity of the lesions, but not in shape
of the profile, revealing the identity of the causative
agents. One of us reported the absence of similarity
between sCJD (six cases) and U.K. scrapie (eight cases)
in transmission characteristics in mice (4). Herein, we
made the striking observation that the French natural
scrapie strain (but not the U.S. scrapie strain) has
the same lesion profile and transmission times in
C57BL/6 mice as do the two human TSE strains studied.
This strain "affiliation" was confirmed biochemically.
There is no epidemiological evidence for a link between
sheep scrapie and the occurrence of CJD in humans (25).
However, such a link, if it is not a general rule,
would be extremely difficult to establish because of
the very low incidence of CJD as well as the existence
of different isolates in humans and multiple strains in
scrapie. Moreover, scrapie is transmissible to nonhuman
primates (26). Thus, there is still a possibility that
in some instances TSE strains infecting humans do share
a common origin with scrapie, as pointed out by our
findings.
snip...
http://www.pnas.org/cgi/content/full/041490898v1
1: J Infect Dis 1980 Aug;142(2):205-8
Oral transmission of kuru, Creutzfeldt-Jakob disease,
and scrapie to nonhuman primates.
Gibbs CJ Jr, Amyx HL, Bacote A, Masters CL, Gajdusek DC.
Kuru and Creutzfeldt-Jakob disease of humans and
scrapie disease of sheep and goats were transmitted to
squirrel monkeys (Saimiri sciureus) that were exposed
to the infectious agents only by their nonforced
consumption of known infectious tissues. The
asymptomatic incubation period in the one monkey
exposed to the virus of kuru was 36 months; that in the
two monkeys exposed to the virus of Creutzfeldt-Jakob
disease was 23 and 27 months, respectively; and that in
the two monkeys exposed to the virus of scrapie was 25
and 32 months, respectively. Careful physical
examination of the buccal cavities of all of the
monkeys failed to reveal signs or oral lesions. One
additional monkey similarly exposed to kuru has
remained asymptomatic during the 39 months that it has
been under observation.
PMID: 6997404
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6997404&dopt=Abstract
NOTES
Interspecies Transmission of Chronic Wasting Disease
Prions to
Squirrel Monkeys (Saimiri sciureus)
Richard F. Marsh,1? Anthony E. Kincaid,2 Richard A.
Bessen,3 and Jason C. Bartz4*
Department of Animal Health and Biomedical Sciences,
University of Wisconsin, Madison 537061; Department of
Physical Therapy2 and Department of Medical
Microbiology and Immunology,4 Creighton University, Omaha,
Nebraska 68178; and Department of Veterinary Molecular
Biology, Montana
State University, Bozeman, Montana 597183
Received 3 May 2005/Accepted 10 August 2005
Chronic wasting disease (CWD) is an emerging prion
disease of deer and elk. The risk of CWD transmission
to humans following exposure to CWD-infected tissues is
unknown. To assess the susceptibility of nonhuman
primates to CWD, two squirrel monkeys were inoculated
with brain tissue from a CWD-infected mule deer. The
CWD-inoculated squirrel monkeys developed a progressive
neurodegenerative disease and were euthanized at
31 and 34 months postinfection. Brain tissue from the
CWD-infected squirrel monkeys contained the abnormal
isoform of the prion protein, PrP-res, and displayed
spongiform degeneration. This is the first reported
transmission of CWD to primates.
snip...
JOURNAL OF VIROLOGY, Nov. 2005, p. 13794-13796 Vol.
79, No. 21
0022-538X/05/$08.00!0
doi:10.1128/JVI.79.21.13794-13796.2005
Copyright © 2005, American Society for Microbiology.
All Rights Reserved.
=============================================
Full Text
Diagnosis and Reporting of Creutzfeldt-Jakob Disease
Singeltary, Sr et al.
JAMA.2001; 285: 733-734
http://jama.ama-assn.org/cgi/content/full/285/6/733?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=dignosing+and+reporting+creutzfeldt+jakob+disease&searchid=1048865596978_1528&stored_search=&FIRSTINDEX=0&journalcode=jama
http://www.neurology.org/cgi/eletters/60/2/176#535
LANCET INFECTIOUS DISEASE JOURNAL
Volume 3, Number 8 01 August 2003
Newsdesk
Tracking spongiform encephalopathies in North America
http://infection.thelancet.com/journal/journal.isa
BMJ
http://www.bmj.com/cgi/eletters/319/7220/1312/b#EL2
BMJ
http://www.bmj.com/cgi/eletters/320/7226/8/b#EL1
TSS
Subject: UK Strategy for Research and Development on Human and Animal Health Aspects of TSEs 2005-2008
Date: February 12, 2006 at 1:08 pm PST
UK Strategy for Research and Development on Human and Animal Health Aspects of Transmissible Spongiform Encephalopathies
2005-2008
snip...
v6.1
Preface
Since the announcement in 1996 of a possible link between BSE in cattle and vCJD in humans two strategy documents for research and development into transmissible spongiform encephalopathies (TSEs) have been produced by the UK government. TSE research has advanced significantly during the past few years, and as senior representatives of the UK public funders of TSE research, we considered it timely to review the current understanding of these diseases and set out a new research strategy that reflected the changes in knowledge.
This document represents the first UK joint human and animal health strategy for TSE research and addresses issues that affect livestock, the food chain and public health. It highlights the improved co-ordination that has taken place between government departments since the publication of the Phillips Report and reflects the overlapping issues of relevance to both human and animal health.
In the production of this document, we have drawn on a wide range of advice from all of the UK's major funders of TSE research and from members of specialist advisory committees such as SEAC, which are detailed within. We have also undertaken wide consultation in the UK and overseas in an attempt to ensure the accuracy of the information included. We are particularly indebted to Professor Chris Bostock (formerly director of the Institute for Animal Health) for his 2004 review of the science, which forms the backbone of this document.
With numbers of BSE cases continuing to fall and vCJD cases apparently stabilising in the UK, it would be easy to be complacent. However, the increasing incidence of chronic wasting disease in the USA reinforces the concern that TSEs are an international problem and one that will need to be monitored carefully for a number of years. In the UK, there remain key issues that continue to pose threats to animal and human health. Not least is the possibility of a non-symptomatic carrier state or the emergence of BSE-like illness in another species such as sheep.
While every attempt is made to reduce exposure to disease it is not always possible to eradicate it completely. Disease management is thus often based on risk assessments of potential exposure and these are based on the latest scientific results.
This document aims to highlight the major scientific uncertainties relating to TSEs and how these will be addressed by the research and development strategies of the major UK funders. The necessary experience of managing BSE and producing scientific evidence upon which to base control policies has led to the development of an extensive UK research base in human and animal health aspects of TSEs.
The UK has a special responsibility to share its expertise in TSEs with Europe and the rest of the world to minimise the effects of TSE infection in other countries.
Although considerable progress has been made, further studies are required to fill in the many gaps in our basic understanding of TSEs and in our knowledge of how TSE epidemics can be effectively controlled. It is therefore vital that the UK research base is maintained and that a co-ordinated and effective funding strategy is adopted for new research. Science develops and inevitably this strategy will require regular reassessment.
3v6.1
Professor Sir John Pattison
Director of Research
Department of Health
Dr John Bell
Chief Executive
Food Standards Agency
Professor Colin Blakemore FRS
Chief Executive
Medical Research Council
Professor Julia Goodfellow CBE
Chief Executive
Biotechnology and Biological Sciences Research Council
Professor Howard Dalton FRS
Chief Scientific Adviser
Department for Environment, Food and Rural Affairs
4v6.1
Executive Summary
1. Transmissible spongiform encephalopathies (TSEs) have been present in human and animal populations for centuries. Interest in them has intensified since BSE became significant in British cattle in the 1990s and especially since its human version became a hazard to the UK population.
2. The number of human fatalities from TSEs in the UK is relatively small, in the low hundreds, and on this criterion TSEs currently appear to present a smaller risk to public health risk than vascular disorders such as heart disease or strokes, which are the UK's biggest killers, or cancers.
3. However, the impact of TSEs has been high and they remain important for a number of reasons. There may be human TSEs with longer latency periods than those that have appeared clinically to date. This could mean a further cost in terms of human life and suffering and to the healthcare system, where considerable resource has already been committed to importing blood products and improving safety measures such as the decontamination of surgical instruments. Identification of another TSE in another species (e.g. BSE in sheep) would affect consumer confidence in British produce, which would add a further burden to a slowly recovering farming and meat industry.
4. The five major UK funders of TSE research each have their own remits, strategies and approaches. The Department of Health and the Department for Environment, Food and Rural Affairs are government departments with responsibility for human and animal health, the environment and the agricultural industry. The Food Standards Agency is a public body established to protect the public from food hazards. The Medical Research Council and the Biotechnology and Biological Sciences Research Council are non-departmental public bodies that fund research in human and animal biology and health.
5. These bodies have different but related interests in TSE research. Although the research councils pay attention to the applicability of the research they fund, they have a strong interest in pursuing excellent science independently of its possible use. The three government departments have responsibilities for human and animal health, and for the environmental and economic ramifications of TSEs, and require sound scientific information on which to base their policies.
6. These organisations are currently (2004/05) spending approximately £35M per year on TSE research. The programmes supported by the five funders are coordinated and discussed with other interested organisations, including devolved UK administrations, the voluntary sector, industry and organisations outside the UK, including the European Commission and research groups in the USA. Central to this cooperation is the TSE R & D Funders Co-ordination Group.
7. Research on TSEs will continue to be necessary in part because of their economic consequences for agriculture, an industry that is already under pressure from a variety of sources. The National Scrapie Plan, which involves eliminating scrapie from the UK sheep flock by removing sheep with lower levels of genetic resistance to it, is costly and requires an adequate base of research knowledge. Furthermore, as a large proportion of the UK population may have been exposed to BSE-contaminated material, the implications for public health and the additional burden on the NHS could be severe. Consequently it is imperative that accurate estimates of the size of the human epidemic are obtained, methods to prevent its spread are continually updated and potential treatments investigated.
5v6.1
8. Research in this area, especially that funded by the research councils, forms part of the general process of advancing knowledge as well as being of practical value. It has been informed by, and in turn informs, advances in our understanding of protein and gene science, and knowledge of human and animal epidemiology. It illuminates important areas of knowledge such as the strength and nature of species barriers and infection processes, including species-to-species and possible mother-to-offspring transmission.
9. Currently, TSEs are one of the rare disease groups where infection leads invariably to death. For this reason, possible treatments are a target for both human and animal TSE research. These might take the form of drug therapy or immunological interventions such as vaccines. If developed for the human population, such interventions would have a high value for patients and their families despite the small number of people affected.
10. TSE research is a growing international field in which the UK has made a significant contribution. The UK is likely to be a valued partner in TSE research for other nations and for international organisations. TSE research has featured in previous European Commission framework programmes for research and is likely to be further funded under the sixth framework programme. The UK is a leader in TSE science and in the cross-agency organisation needed to support the full range of TSE research.
11. The approach to TSE research described in this report includes a number of short-term targets. One of the most pressing is the need for a preclinical diagnostic test for humans and animals. Also important is work on the safety of medical instruments, which is needed by the Department of Health and the UK National Health Service. Other health-related research is directed towards the needs of agencies such as the National Blood Service, which has an interest in blood transfusion hazards. Research is also being pursued on methods for monitoring food for TSE hazards, on animal feed hazards and on animal slaughter practices. This is of interest to Defra and the FSA. Defra has a strong interest in research to support the National Scrapie Plan, to investigate the possibility of BSE in sheep and to establish the risk of TSEs in other farmed animals.
12. The aim of this research is to uncover the science of TSEs, in particular their nature and means of transmission; to develop countermeasures at many points in the food chain; to protect the health of the UK population; and to engage the public in the research and its application.
6v6.1
Introduction
snip...
2.15.3.2 It is difficult to ensure that all cases of vCJD are correctly diagnosed and reported and there is always the worry that some could be missed. Variant CJD occurs in a much younger age group than sporadic CJD68 and it is a concern that cases are perhaps being missed in children and older adults. A survey of over 1,000 children with progressive intellectual and neurological deterioration (PIND), a group that would include vCJD patients, found only previously reported cases of vCJD, indicating that vCJD in children is not being missed68, 314. Although vCJD has been diagnosed in a 74 year old patient315, the possibility remains that cases of vCJD are being missed amongst the elderly. One attempt to estimate the prevalence of infection, as opposed to the incidence of clinical vCJD, is based on a search for the characteristic presence of PrPSc in infected lymphoid tissue in archived specimens of tonsils and appendices removed from patients aged 10 to 50 between 1995 and 1999. The interim findings of this study reported one PrPSc-positive appendix amongst 8318 samples examined, which gives an estimated detectable prevalence of PrPSc accumulation in 120 per million of the population316. However, the finding of a further two PrPSc-positive samples, giving a total of three positive samples in 12 674 samples examined, confirm the wisdom of screening the larger number of samples being collected as part of the National Tonsil Archive333.
snip...
2.2 The prion and other hypotheses
2.2.1 An animal with a TSE infection commonly exhibits an abnormal form (PrPSc or prion) of the cellular prion protein (PrPC). Deposits of PrPSc can take many forms ranging from diffuse widespread distribution to local concentrations of highly ordered aggregates, called amyloid plaques. Deposits of PrPSc can be identified under the microscope in sections of body tissue by selective staining and can be separated from PrPC because PrPSc is insoluble and relatively resistant to protease enzymes used to digest proteins.
2.2.2 The correlation between TSE infection and PrPSc led to the prion hypothesis, that the abnormal form of prion protein is the infectious agent8, 9, 10. Although accepted by many in
19v6.1
the field today, it was highly contentious at first because it went against the then-accepted view that all inherited biological information must be encoded in nucleic acid, DNA or RNA. Alternative hypotheses for the infectious agent include a conventional virus of unknown type11 or a "virino"- an informational molecule, expected to be a small piece of nucleic acid, which is not encoded in the host and which codes for its own replication and binds to the prion protein12.
2.2.3 To date neither a virus nor a virino nucleic acid has been found and most research has focussed on the PrP molecule. Although progress has been made in understanding the structure, function and role in disease of various forms of PrP, the molecular basis of its suggested infectiousness and how it is propagated have not been described. Nor has normal PrP been converted into an infectious form in a test tube in a laboratory, which would provide a formal proof of the hypothesis.
snip...
2.5.4 Many strains of TSEs, even those that have been biologically cloned by repeated passage within a species, can change their characteristics when transmitted from one species to another. This is perhaps not surprising, if the prion hypothesis is correct, given that different species have PrPCs with different amino acid sequences. BSE has been transmitted to a number of different species either "naturally", through contaminated food, as with cats, exotic ruminants, and humans, or experimentally, through injection or feeding, for example sheep, goats and pigs. Each of these species has a different PrPC, but where it has been tested, the strain characteristics of their BSE-derived TSEs are the same as for BSE from cattle. This "stability" of the BSE strain in different PrP backgrounds challenges the notion that shape of PrP in PrPSc encodes the properties of a strain. The shape that, according to the prion hypothesis, defines the BSE strain must be independent of differences, often large, between the amino acid sequence in PrPC. Alternatively, there may be one or more other molecules (yet to be identified) that associate with PrP to determine the strain properties. Knowing the molecular basis of TSE strains is, therefore, at the heart of understanding the nature of the TSE agent.
snip...
3.3.2.4 The prion protein has not been unequivocally shown to be the infectious agent of TSE disease. Although some work is investigating the correlation between PrPSc and infectivity, using transgenic mouse models, this remains a fundamental gap in knowledge. The unequivocal identification of the TSE agent would have a profound effect on the development of appropriate diagnostic tests. For this reason, the search for a non-PrPSc marker for disease is important. Some work is ongoing in the search for alternative markers, using approaches such as metabolomics and proteomics. These approaches search for consistent differences between control and infected animals at several stages of the incubation period. However, an alternative marker for the detection of the disease has not yet been identified. Further characterisation of different conformers of PrP after digestion with proteases and the development and application of other conformation-dependent techniques for detecting PrPSc may allow a better understanding of the significance of atypical results observed in large-scale surveillance studies.
snip...
3.3.3 Prospects for treatment
3.3.3.1 Current strategies involve screening large pharmaceutical libraries to identify possible therapeutic compounds. However, a better understanding of the structures of prion proteins and their biology could lead to a more targeted approach, allowing the design of small molecules which could block abnormal prion protein formation. Approaches underpinning the development of therapeutics remain a priority for the research councils. The identification of a natural mechanism for clearing infectivity from the body could also be exploited for therapeutic purposes.
3.3.3.2 It seems unlikely that a treatment will become available soon to repair damage to the CNS. The research councils fund work on the generic development of stem cell therapy. However, therapies that seek to repair damaged tissue are far in the future and even then would only be of value once infection had been halted. While several strategies to develop a therapeutic are aimed at inhibiting PrPC to PrPSc conversion, success is likely to be improved by the development of good diagnostics to identify individuals with pre-clinical infection.
3.3.3.3 The development and evaluation of a potential therapy is a detailed process that usually takes many years. In addition to continued support for such work, DH and MRC are establishing the infrastructure for rapid clinical evaluation of any agents that have demonstrated anti-prion activity in animals or in vitro. To this end a clinical trial protocol has been developed in conjunction with families and carers through the Medical Research Council's Prion Unit and Clinical Trials Unit, and building capacity for undertaking such work remains a priority.
53
snip...
3.4.0.7 The possibility of an infectious carrier state in apparently healthy animals and humans highlights our limited knowledge of TSE diseases. Work on TSEs may also produce results that have significance for the understanding of other groups of diseases
54v6.1
such as the neurodegenerative changes involved in Alzheimer's and other amyloid brain diseases. A full understanding of TSE transmission is likely to require advances in the understanding of the immune system and will provide insights into aspects of human and animal genetic variability. The Research Councils (BBSRC and MRC) support this underpinning biomedical science.
snip...
3.4.2 The MRC has identified the following key areas in which it would like to continue to receive innovative research proposals:
. The biological and epidemiological relationship between CJD and BSE;
. Epidemiological modelling of CJD;
. The analysis, perception and communication of risk in relation to CJD;
. Early disease progression and diagnosis in life including in vivo imaging approaches, with a focus on the development of non-invasive pre-clinical tests for human TSE diseases, particularly vCJD, e.g. a blood test or throat swab;*
. Integrated molecular, epidemiological and clinical approaches to understanding the cause or causes of sporadic CJD and the relationship with atypical dementias;
. Molecular, genetic, cellular and functional approaches to elucidating mechanisms of TSEs transmission, PrP replication, pathogenesis and clinical progression, with a view to improving understanding of how TSEs cause disease, particularly during the very early stages;*
. The biological function of normal prion protein (PrP);*
. The molecular structure of the prion proteins;*
. Development and improvement of animal models and cell culture systems;*
. Development of approaches to reduce secondary (iatrogenic) infection;*
. Rational approaches to developing therapy including vaccine based treatment approaches.*
* Council has approved programmes of work within these areas at the MRC Prion Unit
55
http://www.mrc.ac.uk/pdf-about-tse_uk_strategy_june2005.pdf
Coexistence of multiple PrPSc types in individuals with
Creutzfeldt-Jakob disease
Magdalini Polymenidou, Katharina Stoeck, Markus
Glatzel, Martin Vey, Anne Bellon, and Adriano Aguzzi
Summary
Background The molecular typing of sporadic
Creutzfeldt-Jakob disease (CJD) is based on the size
and glycoform
ratio of protease-resistant prion protein (PrPSc), and
on PRNP haplotype. On digestion with proteinase K, type
1 and
type 2 PrPSc display unglycosylated core fragments of
21 kDa and 19 kDa, resulting from cleavage around amino
acids 82 and 97, respectively.
Methods We generated anti-PrP monoclonal antibodies to
epitopes immediately preceding the differential proteinase
K cleavage sites. These antibodies, which were
designated POM2 and POM12, recognise type 1, but not
type 2, PrPSc.
Findings We studied 114 brain samples from 70 patients
with sporadic CJD and three patients with variant CJD.
Every patient classified as CJD type 2, and all variant
CJD patients, showed POM2/POM12 reactivity in the
cerebellum and other PrPSc-rich brain areas, with a
typical PrPSc type 1 migration pattern.
Interpretation The regular coexistence of multiple
PrPSc types in patients with CJD casts doubts on the
validity of
electrophoretic PrPSc mobilities as surrogates for
prion strains, and questions the rational basis of
current CJD
classifications.
snip...
The above results set the existing CJD classifications
into debate and introduce interesting questions about
human CJD types. For example, do human prion types
exist in a dynamic equilibrium in the brains of affected
individuals? Do they coexist in most or even all CJD
cases? Is the biochemically identified PrPSc type simply
the dominant type, and not the only PrPSc species?
Published online October 31, 2005
http://neurology.thelancet.com
Detection of Type 1 Prion Protein in Variant
Creutzfeldt-Jakob Disease
Helen M. Yull,* Diane L. Ritchie,*
Jan P.M. Langeveld,? Fred G. van Zijderveld,?
Moira E. Bruce,? James W. Ironside,* and
Mark W. Head*
From the National CJD Surveillance Unit,* School of
Molecular
and Clinical Medicine, University of Edinburgh, Edinburgh,
United Kingdom; Central Institute for Animal Disease
Control
(CIDC)-Lelystad, ? Lelystad, The Netherlands; Institute
for Animal
Health, Neuropathogenesis Unit, ? Edinburgh, United Kingdom
Molecular typing of the abnormal form of the prion
protein (PrPSc) has come to be regarded as a powerful
tool in the investigation of the prion diseases. All
evidence
thus far presented indicates a single PrPSc molecular
type in variant Creutzfeldt-Jakob disease (termed
type 2B), presumably resulting from infection with a
single strain of the agent (bovine spongiform
encephalopathy).
Here we show for the first time that the PrPSc
that accumulates in the brain in variant Creutzfeldt-
Jakob disease also contains a minority type 1 component.
This minority type 1 PrPSc was found in all 21
cases of variant Creutzfeldt-Jakob disease tested,
irrespective
of brain region examined, and was also
present in the variant Creutzfeldt-Jakob disease tonsil.
The quantitative balance between PrPSc types was maintained
when variant Creutzfeldt-Jakob disease was
transmitted to wild-type mice and was also found in
bovine spongiform encephalopathy cattle brain, indicating
that the agent rather than the host specifies their
relative representation. These results indicate that PrPSc
molecular typing is based on quantitative rather than
qualitative phenomena and point to a complex relationship
between prion protein biochemistry, disease phenotype
and agent strain. (Am J Pathol 2006, 168:151-157;
DOI: 10.2353/ajpath.2006.050766)
snip...
Discussion
In the apparent absence of a foreign nucleic acid genome
associated with the agents responsible for transmissible
spongiform encephalopathies or prion diseases,
efforts to provide a molecular definition of agent strain
have focused on biochemical differences in the abnormal,
disease-associated form of the prion protein, termed
PrPSc. Differences in PrPSc conformation and glycosylation
have been proposed to underlie disease phenotype
and form the biochemical basis of agent strain. This
proposal has found support in the observation that the
major phenotypic subtypes of sCJD appear to correlate
with the presence of either type 1 or type 2 PrPSc in
combination with the presence of either methionine or
valine at codon 129 of the prion protein gene.2 Similarly,
the PrPSc type associated with vCJD correlates with the
presence of type 2 PrPSc and is distinct from that found in
sCJD because of a characteristically high occupancy of
both N-linked glycosylation sites (type 2B).6,11 The
means by which such conformational difference is detected
is somewhat indirect; relying on the action of proteases,
primarily proteinase K, to degrade the normal
Figure 6. Type 1 PrPSc is a stable minority component
of PrPSc from the vCJD
brain. Western blot analysis of PrP in a sample of
cerebral cortex from a
case
of vCJD during digestion with proteinase K is shown.
Time points assayed
are indicated in minutes (T0, 5, 10, 30, 60, 120, 180).
Duplicate blots were
probed with 3F4, which detects both type 1 and type 2
PrPSc, and with 12B2,
which detects type 1. The insert shows a shorter
exposure of the same time
course study from a separate experiment also probed
with 3F4. Both blots
included samples of cerebral cortex from a case of
sporadic CJD MM1 (Type
1) and molecular weight markers (Markers) indicate
weights in kd.
Figure 7. A minority type 1-like PrPSc is found in vCJD
tonsil, vCJD
transmitted
to mice and in BSE. Western blot analysis of PrPSc in a
concentrated
sample of tonsil from a case of vCJD (Tonsil), in a
concentrated brain
sample
of a wild-type mouse (C57BL) infected with vCJD and in
a sample of cattle
BSE brain (BSE) is shown. Tissue extracts were digested
with proteinase K.
Duplicate blots were probed with either 3F4 or 6H4,
both of which detect
type 1 and type 2 PrPSc, and with 12B2, which detects
type 1. The blots
included samples of cerebral cortex from a case of
sporadic CJD MM1 (Type
1) and molecular weight markers (Markers) indicate
weights in kd.
Type 1 PrPSc in Variant Creutzfeldt-Jakob Disease 155
AJP January 2006, Vol. 168, No. 1
cellular form of PrP and produce a protease-resistant
core fragment of PrPSc that differs in the extent of its
N-terminal truncation according to the original
conformation.
A complication has recently arisen with the finding that
both type 1 and type 2 can co-exist in the brains of
patients with sCJD.2,5-8 More recently this same phenomenon
has been demonstrated in patients with iatrogenically
acquired and familial forms of human prion disease.
9,10 The existence of this phenomenon is now
beyond doubt but its prevalence and its biological
significance
remain a matter of debate.
Conventional Western blot analysis using antibodies
that detect type 1 and type 2 PrPSc has severe quantitative
limitations for the co-detection of type 1 and type 2
PrPSc in individual samples, suggesting that the prevalence
of co-occurrence of the two types might be underestimated.
We have sought to circumvent this problem by
using an antibody that is type 1-specific and applied this
to the sole remaining human prion disease where the
phenomenon of mixed PrPSc types has not yet been
shown, namely vCJD.
These results show that even in vCJD where susceptible
individuals have been infected supposedly by a
single strain of agent, both PrPSc types co-exist: a
situation
reminiscent of that seen when similarly discriminant
antibodies were used to analyze experimental BSE in
sheep.14,17 In sporadic and familial CJD, individual
brains can show a wide range of relative amounts of the
two types in samples from different regions, but where
brains have been thoroughly investigated a predominant
type is usually evident.2,6,10 This differs from this
report
on vCJD, where type 1 is present in all samples
investigated
but always as a minor component that never
reaches a level at which it is detectable without a type
1-specific antibody. It would appear that the relative
balance
between type 1 and type 2 is controlled within
certain limits in the vCJD brain. A minority type-1-like
band is also detected by 12B2 in vCJD tonsil, in BSE
brain and in the brains of mice experimentally infected
with vCJD, suggesting that this balance of types is agent,
rather than host or tissue, specific. Interestingly the
"glycoform
signature" of the type 2 PrPSc found in vCJD (type
2B) is also seen in the type 1 PrPSc components, suggesting
that it could legitimately be termed type 1B.
PrPSc isotype analysis has proven to be extremely
useful in the differential diagnosis of CJD and is
likely to
continue to have a major role in the investigation of human
prion diseases. However, it is clear, on the basis of
these findings, that molecular typing has quantitative
limitations
and that any mechanistic explanation of prion
replication and the molecular basis of agent strain
variation
must accommodate the co-existence of multiple
prion protein conformers. Whether or not the different
conformers we describe here correlate in a simple and
direct way with agent strain remains to be determined. In
principle two interpretations present themselves: either
the two conformers can be produced by a single strain of
agent or vCJD (and, therefore, presumably BSE) results
from a mixture of strains, one of which generally
predominates.
Evidence for the isolation in mice of more than one
strain from individual isolates of BSE has been presented
previously.18,19
One practical consequence of our findings is that the
correct interpretation of transmission studies will depend
on a full examination of the balance of molecular types
present in the inoculum used to transmit disease, in
addition
to a thorough analysis of the molecular types that
arise in the recipients. Another consequence relates to
the diagnostic certainty of relying on PrPSc molecular
type alone when considering the possibility of BSE
infection
or secondary transmission in humans who have a
genotype other than methionine at codon 129 of the
PRNP gene. In this context it is interesting to note
that this
minority type 1B component resembles the type 5 PrPSc
described previously to characterize vCJD transmission
into certain humanized PRNP129VV transgenic mouse
models.12,20 This apparently abrupt change in molecular
phenotype might represent a selection process imposed
by this particular transgenic mouse model. Irrespective of
whether this proves to be the case, the results shown
here point to further complexities in the relationship
between
the physico-chemical properties of the prion protein,
human disease phenotype, and prion agent strain.
Acknowledgments
snip...
Type 1 PrPSc in Variant Creutzfeldt-Jakob Disease 157
AJP January 2006, Vol. 168, No. 1 ...TSS
http://ajp.amjpathol.org/cgi/content/abstract/168/1/151maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=prion&searchid=1136646133963_237&FIRSTINDEX=0&volume=168&issue=1&journalcode=amjpathol
Neuropathology and Applied Neurobiology
(2005),
31
, 565-579 doi: 10.1111/j.1365-2990.2005.00697.x
© 2005 Blackwell Publishing Ltd
565
Blackwell Science, LtdOxford, UKNANNeuropathology and
Applied Neurobiology0305-1846Blackwell Publishing Ltd, 2005
316565579
Review article
Phenotypic variability in human prion diseases
J. W. Ironside, D. L. Ritchie and M. W. Head
National Creutzfeldt-Jakob Disease Surveillance Unit,
Division of Pathology, University of Edinburgh,
Edinburgh, UK
J. W. Ironside, D. L. Ritchie and M. W. Head (2005)
Neuropathology and Applied Neurobiology
31,
565-579
Phenotypic variability in human prion diseases
Human prion diseases are rare neurodegenerative disorders
that can occur as sporadic, familial or acquired disorders.
Within each of these categories there is a wide range
of phenotypic variation that is not encountered in other
neurodegenerative disorders. The identification of the
prion protein and its key role in the pathogenesis of this
diverse group of diseases has allowed a fuller
understanding
of factors that influence disease phenotype. In particular,
the naturally occurring polymorphism at codon 129
in the prion protein gene has a major influence on the
disease
phenotype in sporadic, familial and acquired prion
diseases, although the underlying mechanisms remain
unclear. Recent technical advances have improved our
ability to study the isoforms of the abnormal prion protein
in the brain and in other tissues. This has lead to the
concept
of molecular strain typing, in which different isoforms
of the prion protein are proposed to correspond to
individual strains of the transmissible agent, each with
specific biological properties. In sporadic
Creutzfeldt-Jakob
disease there are at least six major combinations of codon
129 genotype and prion protein isotype, which appear to
relate to distinctive clinical subgroups of this disease.
However, these relationships are proving to be more complex
than first considered, particularly in cases with more
than a single prion protein isotype in the brain. Further
work is required to clarify these relationships and to
explain the mechanism of neuropathological targeting of
specific brain regions, which accounts for the diversity of
clinical features within human prion diseases.
© 2005 Blackwell Publishing Ltd, Neuropathology and
Applied Neurobiology, 31, 565-579
===================================
BSE prions propagate as either variant CJD-like or
sporadic CJD-like prion strains in transgenic mice
expressing human prion protein
The EMBO Journal Vol. 21 No. 23 pp. 6358±6366, 2002
Emmanuel A.Asante, Jacqueline M.Linehan,
Melanie Desbruslais, Susan Joiner,
Ian Gowland, Andrew L.Wood, Julie Welch,
Andrew F.Hill, Sarah E.Lloyd,
Jonathan D.F.Wadsworth and
John Collinge1
MRC Prion Unit and Department of Neurodegenerative Disease,
Institute of Neurology, University College, Queen Square,
London WC1N 3BG, UK
1Corresponding author
e-mail: j.collinge@prion.ucl.ac.uk.
Variant Creutzfeldt±Jakob disease (vCJD) has been
recognized to date only in individuals homozygous for
methionine at PRNP codon 129. Here we show that
transgenic mice expressing human PrP methionine
129, inoculated with either bovine spongiform
encephalopathy (BSE) or variant CJD prions, may
develop the neuropathological and molecular phenotype
of vCJD, consistent with these diseases being
caused by the same prion strain. Surprisingly, however,
BSE transmission to these transgenic mice, in
addition to producing a vCJD-like phenotype, can also
result in a distinct molecular phenotype that is
indistinguishable
from that of sporadic CJD with PrPSc
type 2. These data suggest that more than one BSEderived
prion strain might infect humans; it is therefore
possible that some patients with a phenotype consistent
with sporadic CJD may have a disease arising
from BSE exposure.
snip...
These studies further strengthen the evidence that vCJD
is caused by a BSE-like prion strain. Also, remarkably, the
key neuropathological hallmark of vCJD, the presence of
abundant ¯orid PrP plaques, can be recapitulated on BSE
or vCJD transmission to these mice. However, the most
surprising aspect of the studies was the ®nding that an
alternate pattern of disease can be induced in 129MM
Tg35 mice from primary transmission of BSE, with a
molecular phenotype indistinguishable from that of a
subtype
of sporadic CJD. This ®nding has important potential
implications as it raises the possibility that some humans
infected with BSE prions may develop a clinical disease
indistinguishable from classical CJD associated with type 2
PrPSc. This is, in our experience, the commonest molecular
sub-type of sporadic CJD. In this regard, it is of interest
that the reported incidence of sporadic CJD has risen
in the
UK since the 1970s (Cousens et al., 1997). This has been
attributed to improved case ascertainment, particularly as
much of the rise is reported from elderly patients and
similar rises in incidence were noted in other European
countries without reported BSE (Will et al., 1998).
However, it is now clear that BSE is present in many
European countries, albeit at a much lower incidence than
was seen in the UK. While improved ascertainment is
likely to be a major factor in this rise, that some of
these
additional cases may be related to BSE exposure cannot be
ruled out. It is of interest in this regard that a 2-fold
increase in the reported incidence of sporadic CJD in 2001
has recently been reported for Switzerland, a country that
had the highest incidence of cattle BSE in continental
Europe between 1990 and 2002 (Glatzel et al., 2002). No
epidemiological case±control studies with strati®cation of
CJD cases by molecular sub-type have yet been reported.
It will be important to review the incidence of sporadic
CJD associated with PrPSc type 2 and other molecular
subtypes
in both BSE-affected and unaffected countries in the
light of these ®ndings. If human BSE prion infection can
result in propagation of type 2 PrPSc, it would be expected
that such cases would be indistinguishable on clinical,
pathological and molecular criteria from classical CJD. It
may also be expected that such prions would behave
biologically like those isolated from humans with sporadic
CJD with type 2 PrPSc. The transmission properties of
prions associated with type 2 PrPSc from BSE-inoculated
129MM Tg35 mice are being investigated by serial
passage.
We consider these data inconsistent with contamination
of some of the 129MM Tg35 mice with sporadic CJD
prions. These transmission studies were performed according
to rigorous biosafety protocols for preparation of
inocula and both the inoculation and care of mice, which
are all uniquely identi®ed by sub-cutaneous transponders.
However, crucially, the same BSE inocula have been used
on 129VV Tg152 and 129MM Tg45 mice, which are
highly sensitive to sporadic CJD but in which such
transmissions producing type 2 PrPSc were not observed.
Furthermore, in an independent experiment, separate
inbred lines of wild-type mice, which are highly resistant
to sporadic CJD prions, also propagated two distinctive
PrPSc types on challenge with either BSE or vCJD. No
evidence of spontaneous prion disease or PrPSc has been
seen in groups of uninoculated or mock-inoculated aged
129MM Tg35 mice.
While distinctive prion isolates have been derived from
BSE passage in mice previously (designated 301C and
301V), these, in contrast to the data presented here, are
propagated in mice expressing different prion proteins
(Bruce et al., 1994). It is unclear whether our ®ndings
indicate the existence of more than one prion strain in
individual cattle with BSE, with selection and preferential
replication of distinct strains by different hosts, or that
`mutation' of a unitary BSE strain occurs in some types of
host. Western blot analysis of single BSE isolates has not
shown evidence of the presence of a proportion of
monoglycosylated dominant PrPSc type in addition to the
diglycosylated dominant pattern (data not shown).
Extensive strain typing of large numbers of individual
BSE-infected cattle either by biological or molecular
methods has not been reported.
Presumably, the different genetic background of the
different inbred mouse lines is crucial in determining
which prion strain propagates on BSE inoculation. The
transgenic mice described here have a mixed genetic
background with contributions from FVB/N, C57BL/6 and
129Sv inbred lines; each mouse will therefore have a
different genetic background. This may explain the
differing response of individual 129MM Tg35 mice, and
the difference between 129MM Tg35 and 129MM Tg45
mice, which are, like all transgenic lines, populations
derived from single founders. Indeed, the consistent
distinctive strain propagation in FVB and C57BL/6 versus
SJL and RIIIS lines may allow mapping of genes relevant
to strain selection and propagation, and these studies
are in
progress.
That different prion strains can be consistently isolated
in different inbred mouse lines challenged with BSE
prions argues that other species exposed to BSE may
develop prion diseases that are not recognizable as being
caused by the BSE strain by either biological or molecular
strain typing methods. As with 129MM Tg35 mice, the
prions replicating in such transmissions may be
indistinguishable
from naturally occurring prion strains. It
remains of considerable concern whether BSE has transmitted
to, and is being maintained in, European sheep
¯ocks. Given the diversity of sheep breeds affected by
scrapie, it has to be considered that some sheep might have
become infected with BSE, but propagated a distinctive
strain type indistinguishable from those of natural sheep
scrapie. ...
The EMBO Journal Vol. 21 No. 23 pp. 6358±6366, 2002
6358 ãEuropean Molecular Biology Organization
http://embojournal.npgjournals.com/cgi/reprint/21/23/6358
J Neuropsychiatry Clin Neurosci 17:489-495, November 2005
doi: 10.1176/appi.neuropsych.17.4.489
© 2005 American Psychiatric Publishing, Inc.
Psychiatric Manifestations of Creutzfeldt-Jakob
Disease: A 25-Year Analysis
Christopher A. Wall, M.D., Teresa A. Rummans, M.D.,
Allen J. Aksamit, M.D.,
Lois E. Krahn, M.D. and V. Shane Pankratz, Ph.D.
Received April 20, 2004; revised September 9, 2004;
accepted September 13,
2004. From the Mayo Clinic, Department of Psychiatry
and Psychology,
Rochester, Minnesota; Mayo Clinic, Department of
Neurology, Rochester,
Minnesota. Address correspondence to Dr. Wall, Mayo
Clinic, Department of
Psychiatry and Psychology, Mayo Building-W11A, 200
First St., SW, Rochester,
MN 55905; wall.chris@mayo.edu. (E-mail).
This study characterizes the type and timing of
psychiatric manifestations
in sporadic Creutzfeldt-Jakob disease (sCJD).
Historically, sCJD has been
characterized by prominent neurological symptoms, while
the variant form
(vCJD) is described as primarily psychiatric in
presentation and course: A
retrospective review of 126 sCJD patients evaluated at
the Mayo Clinic from
1976-2001 was conducted. Cases were reviewed for
symptoms of depression,
anxiety, psychosis, behavior dyscontrol, sleep
disturbances, and
neurological signs during the disease course. Eighty
percent of the cases
demonstrated psychiatric symptoms within the first 100
days of illness, with
26% occurring at presentation. The most commonly
reported symptoms in this
population included sleep disturbances, psychotic
symptoms, and depression.
Psychiatric manifestations are an early and prominent
feature of sporadic
CJD, often occurring prior to formal diagnosis.
snip...
CONCLUSIONS
Historically, psychiatric manifestations have been
described as a relatively
infrequent occurrence in the sporadic form of
creutzfeldt-Jakob disease.
However, our findings suggest otherwise. In this study,
a vast majority of
the cases were noted to have at least one psychiatric
symptom during the
course of illness, with nearly one-quarter occurring in
the prodromal or
presenting phase of the illness. After comparing the
frequency of
neuropsychiatric symptoms in sporadic CJD to studies
describing the variant
form of CJD, we found that there are fewer clinical
differences than
previously reported.5-7 While the age of patients
with vCJD presentation
is significantly younger and the course of illness is
longer, the type and
timing of psychiatric manifestations appear similar
between these two
diseases. ...snip...
http://neuro.psychiatryonline.org/cgi/content/abstract/17/4/489
Personal Communication
-------- Original Message --------
Subject: re-BSE prions propagate as
either variant CJD-like or sporadic CJD Date: Thu, 28
Nov 2002 10:23:43
-0000 From: "Asante, Emmanuel A" To:
"'flounder@wt.net'"
Dear Terry,
I have been asked by Professor Collinge to respond to
your request. I am
a Senior Scientist in the MRC Prion Unit and the lead
author on the
paper. I have attached a pdf copy of the paper for your
attention. Thank
you for your interest in the paper.
In respect of your first question, the simple answer
is, yes. As you
will find in the paper, we have managed to associate
the alternate
phenotype to type 2 PrPSc, the commonest sporadic CJD.
It is too early to be able to claim any further
sub-classification in
respect of Heidenhain variant CJD or Vicky Rimmer's
version. It will
take further studies, which are on-going, to establish
if there are
sub-types to our initial finding which we are now
reporting. The main
point of the paper is that, as well as leading to the
expected new
variant CJD phenotype, BSE transmission to the
129-methionine genotype
can lead to an alternate phenotype which is
indistinguishable from type
2 PrPSc.
I hope reading the paper will enlighten you more on the
subject. If I
can be of any further assistance please to not hesitate
to ask. Best wishes.
Emmanuel Asante
<> ____________________________________
Dr. Emmanuel A Asante MRC Prion Unit & Neurogenetics
Dept. Imperial
College School of Medicine (St. Mary's) Norfolk Place,
LONDON W2 1PG
Tel: +44 (0)20 7594 3794 Fax: +44 (0)20 7706 3272 email:
e.asante@ic.ac.uk. (until 9/12/02)
New e-mail: e.asante@prion.ucl.ac.uk. (active from now)
____________________________________
Human Prion Protein with
Valine 129 Prevents Expression
of Variant CJD Phenotype
Jonathan D. F. Wadsworth, Emmanuel A. Asante,
Melanie Desbruslais, Jacqueline M. Linehan, Susan Joiner,
Ian Gowland, Julie Welch, Lisa Stone, Sarah E. Lloyd,
Andrew F. Hill,* Sebastian Brandner, John Collinge.
Variant Creutzfeldt-Jakob disease (vCJD) is a unique
and highly distinctive
clinicopathological and molecular phenotype of human
prion disease
associated with infection with bovine spongiform
encephalopathy (BSE)-like
prions. Here, we found that generation of this
phenotype in transgenic mice
required expression of human prion protein (PrP) with
methionine 129.
Expression of human PrP with valine 129 resulted in a
distinct phenotype and,
remarkably, persistence of a barrier to transmission of
BSE-derived prions on
subpassage. Polymorphic residue 129 of human PrP
dictated propagation of
distinct prion strains after BSE prion infection. Thus,
primary and secondary
human infection with BSE-derived prions may result in
sporadic CJD-like or
novel phenotypes in addition to vCJD, depending on the
genotype of the prion
source and the recipient.
snip...
3 DECEMBER 2004 VOL 306 SCIENCE
http://www.sciencemag.org
Characterization of two distinct prion strains
derived from bovine spongiform encephalopathy
transmissions to inbred mice
Sarah E. Lloyd, Jacqueline M. Linehan, Melanie Desbruslais,
Susan Joiner, Jennifer Buckell, Sebastian Brandner,
Jonathan D. F. Wadsworth and John Collinge
Correspondence
John Collinge
j.collinge@prion.ucl.ac.uk.
MRC Prion Unit and Department of Neurodegenerative
Disease, Institute of Neurology,
University College, London WC1N 3BG, UK
Received 9 December 2003
Accepted 27 April 2004
Distinct prion strains can be distinguished by
differences in incubation period, neuropathology
and biochemical properties of disease-associated prion
protein (PrPSc) in inoculated mice.
Reliable comparisons of mouse prion strain properties
can only be achieved after passage in
genetically identical mice, as host prion protein
sequence and genetic background are known
to modulate prion disease phenotypes. While multiple
prion strains have been identified in
sheep scrapie and Creutzfeldt-Jakob disease, bovine
spongiform encephalopathy (BSE) is
thought to be caused by a single prion strain. Primary
passage of BSE prions to different lines
of inbred mice resulted in the propagation of two
distinct PrPSc types, suggesting that two
prion strains may have been isolated. To investigate
this further, these isolates were
subpassaged in a single line of inbred mice (SJL) and
it was confirmed that two distinct prion
strains had been identified. MRC1 was characterized by
a short incubation time (110±3 days),
a mono-glycosylated-dominant PrPSc type and a
generalized diffuse pattern of PrP-immunoreactive
deposits, while MRC2 displayed a much longer incubation
time (155±1 days),
a di-glycosylated-dominant PrPSc type and a distinct
pattern of PrP-immunoreactive deposits
and neuronal loss. These data indicate a crucial
involvement of the host genome in modulating
prion strain selection and propagation in mice. It is
possible that multiple disease phenotypes
may also be possible in BSE prion infection in humans
and other animals.
snip...
Journal of General Virology (2004), 85, 2471-2478 DOI
10.1099/vir.0.79889-0
http://vir.sgmjournals.org/cgi/content/abstract/85/8/2471
Medical Sciences
Identification of a second bovine amyloidotic
spongiform encephalopathy: Molecular similarities with
sporadic Creutzfeldt-Jakob disease
Cristina Casalone *, Gianluigi Zanusso , Pierluigi
Acutis *, Sergio Ferrari , Lorenzo Capucci , Fabrizio
Tagliavini ¶, Salvatore Monaco ||, and Maria Caramelli *
*Centro di Referenza Nazionale per le Encefalopatie
Animali, Istituto Zooprofilattico Sperimentale del
Piemonte, Liguria e Valle d'Aosta, Via Bologna, 148,
10195 Turin, Italy; Department of Neurological and
Visual Science, Section of Clinical Neurology,
Policlinico G.B. Rossi, Piazzale L.A. Scuro, 10, 37134
Verona, Italy; Istituto Zooprofilattico Sperimentale
della Lombardia ed Emilia Romagna, Via Bianchi, 9,
25124 Brescia, Italy; and ¶Istituto Nazionale
Neurologico "Carlo Besta," Via Celoria 11, 20133 Milan,
Italy
Edited by Stanley B. Prusiner, University of
California, San Francisco, CA, and approved December
23, 2003 (received for review September 9, 2003)
Transmissible spongiform encephalopathies (TSEs), or
prion diseases, are mammalian neurodegenerative
disorders characterized by a posttranslational
conversion and brain accumulation of an insoluble,
protease-resistant isoform (PrPSc) of the host-encoded
cellular prion protein (PrPC). Human and animal TSE
agents exist as different phenotypes that can be
biochemically differentiated on the basis of the
molecular mass of the protease-resistant PrPSc
fragments and the degree of glycosylation.
Epidemiological, molecular, and transmission studies
strongly suggest that the single strain of agent
responsible for bovine spongiform encephalopathy (BSE)
has infected humans, causing variant Creutzfeldt-Jakob
disease. The unprecedented biological properties of the
BSE agent, which circumvents the so-called "species
barrier" between cattle and humans and adapts to
different mammalian species, has raised considerable
concern for human health. To date, it is unknown
whether more than one strain might be responsible for
cattle TSE or whether the BSE agent undergoes
phenotypic variation after natural transmission. Here
we provide evidence of a second cattle TSE. The
disorder was pathologically characterized by the
presence of PrP-immunopositive amyloid plaques, as
opposed to the lack of amyloid deposition in typical
BSE cases, and by a different pattern of regional
distribution and topology of brain PrPSc accumulation.
In addition, Western blot analysis showed a PrPSc type
with predominance of the low molecular mass glycoform
and a protease-resistant fragment of lower molecular
mass than BSE-PrPSc. Strikingly, the molecular
signature of this previously undescribed bovine PrPSc
was similar to that encountered in a distinct subtype
of sporadic Creutzfeldt-Jakob disease.
--------------------------------------------------------------------------------
C.C. and G.Z. contributed equally to this work.
||To whom correspondence should be addressed.
E-mail: salvatore.monaco@mail.univr.it. .
www.pnas.org/cgi/doi/10.1073/pnas.0305777101
snip...
Phenotypic Similarities Between BASE and sCJD. The
transmissibility
of CJD brains was initially demonstrated in primates
(27), and
classification of atypical cases as CJD was based on
this property
(28). To date, no systematic studies of strain typing
in sCJD have
been provided, and classification of different subtypes
is based
on clinical, neuropathological, and molecular features
(the polymorphic
PRNP codon 129 and the PrPSc glycotype) (8, 9, 15, 19).
The importance of molecular PrPSc characterization in
assessing
the identity of TSE strains is underscored by several
studies,
showing that the stability of given disease-specific
PrPSc types is
maintained upon experimental propagation of sCJD, familial
CJD, and vCJD isolates in transgenic PrP-humanized mice (8,
29). Similarly, biochemical properties of BSE- and
vCJDassociated
PrPSc molecules remain stable after passage to mice
expressing bovine PrP (30). Recently, however, it has been
reported that PrP-humanized mice inoculated with BSE
tissues
may also propagate a distinctive PrPSc type, with a
''monoglycosylated-
dominant'' pattern and electrophoretic mobility of the
unglycosylated fragment slower than that of vCJD and
BSE (31).
Strikingly, this PrPSc type shares its molecular
properties with the
a PrPSc molecule found in classical sCJD. This
observation is at
variance with the PrPSc type found in MV2 sCJD cases and in
cattle BASE, showing a monoglycosylated-dominant
pattern but
faster electrophoretic mobility of the
protease-resistant fragment
as compared with BSE. In addition to molecular properties
of PrPSc, BASE and MV2 sCJD share a distinctive pattern of
intracerebral PrP deposition, which occurs as
plaque-like and
amyloid-kuru plaques. Differences were, however,
observed in
the regional distribution of PrPSc. While inMV2 sCJD
cases the
largest amounts of PrPSc were detected in the cerebellum,
brainstem, and striatum, in cattle BASE these areas
were less
involved and the highest levels of PrPSc were recovered
from the
thalamus and olfactory regions.
In conclusion, decoding the biochemical PrPSc signature of
individual human and animal TSE strains may allow the
identification
of potential risk factors for human disorders with
unknown etiology, such as sCJD. However, although BASE and
sCJD share several characteristics, caution is dictated
in assessing
a link between conditions affecting two different mammalian
species, based on convergent biochemical properties of
diseaseassociated
PrPSc types. Strains of TSE agents may be better
characterized upon passage to transgenic mice. In the
interim
until this is accomplished, our present findings
suggest a strict
epidemiological surveillance of cattle TSE and sCJD
based on
molecular criteria.
http://www.pnas.org/cgi/reprint/0305777101v1
Published online before print March 20, 2001,
10.1073/pnas.041490898
Neurobiology
Adaptation of the bovine spongiform encephalopathy
agent to primates and comparison with Creutzfeldt-
Jakob disease: Implications for human health
Corinne Ida Lasmézas*,, Jean-Guy Fournier*, Virginie
Nouvel*, Hermann Boe*, Domíníque Marcé*, François
Lamoury*, Nicolas Kopp, Jean-Jacques Hauw§, James
Ironside¶, Moira Bruce, Dominique Dormont*, and
Jean-Philippe Deslys*
* Commissariat à l'Energie Atomique, Service de
Neurovirologie, Direction des Sciences du
Vivant/Département de Recherche Medicale, Centre de
Recherches du Service de Santé des Armées 60-68, Avenue
du Général Leclerc, BP 6, 92 265 Fontenay-aux-Roses
Cedex, France; Hôpital Neurologique Pierre Wertheimer,
59, Boulevard Pinel, 69003 Lyon, France; § Laboratoire
de Neuropathologie, Hôpital de la Salpêtrière, 83,
Boulevard de l'Hôpital, 75013 Paris, France; ¶
Creutzfeldt-Jakob Disease Surveillance Unit, Western
General Hospital, Crewe Road, Edinburgh EH4 2XU, United
Kingdom; and Institute for Animal Health,
Neuropathogenesis Unit, West Mains Road, Edinburgh EH9
3JF, United Kingdom
Edited by D. Carleton Gajdusek, Centre National de la
Recherche Scientifique, Gif-sur-Yvette, France, and
approved December 7, 2000 (received for review October
16, 2000)
Abstract
There is substantial scientific evidence to support the
notion that bovine spongiform encephalopathy (BSE) has
contaminated human beings, causing variant
Creutzfeldt-Jakob disease (vCJD). This disease has
raised concerns about the possibility of an iatrogenic
secondary transmission to humans, because the
biological properties of the primate-adapted BSE agent
are unknown. We show that (i) BSE can be transmitted
from primate to primate by intravenous route in 25
months, and (ii) an iatrogenic transmission of vCJD to
humans could be readily recognized pathologically,
whether it occurs by the central or peripheral route.
Strain typing in mice demonstrates that the BSE agent
adapts to macaques in the same way as it does to humans
and confirms that the BSE agent is responsible for vCJD
not only in the United Kingdom but also in France. The
agent responsible for French iatrogenic growth
hormone-linked CJD taken as a control is very different
from vCJD but is similar to that found in one case of
sporadic CJD and one sheep scrapie isolate. These data
will be key in identifying the origin of human cases of
prion disease, including accidental vCJD transmission,
and could provide bases for vCJD risk assessment.
snip...
Characterization of the CJD and Scrapie Strains.
Controls were set up by transmitting one French and one
U.S. scrapie isolate from ruminants as well as French
sCJD and iCJD cases from humans. None of these revealed
a lesion profile or transmission characteristics
similar or close to those of BSE or vCJD, respectively,
thus extending to the present French scrapie isolate
the previous observation that the BSE agent was
different from all known natural scrapie strains (4, 24).
The lesion profiles of sCJD and iCJD differed only
slightly in severity of the lesions, but not in shape
of the profile, revealing the identity of the causative
agents. One of us reported the absence of similarity
between sCJD (six cases) and U.K. scrapie (eight cases)
in transmission characteristics in mice (4). Herein, we
made the striking observation that the French natural
scrapie strain (but not the U.S. scrapie strain) has
the same lesion profile and transmission times in
C57BL/6 mice as do the two human TSE strains studied.
This strain "affiliation" was confirmed biochemically.
There is no epidemiological evidence for a link between
sheep scrapie and the occurrence of CJD in humans (25).
However, such a link, if it is not a general rule,
would be extremely difficult to establish because of
the very low incidence of CJD as well as the existence
of different isolates in humans and multiple strains in
scrapie. Moreover, scrapie is transmissible to nonhuman
primates (26). Thus, there is still a possibility that
in some instances TSE strains infecting humans do share
a common origin with scrapie, as pointed out by our
findings.
snip...
http://www.pnas.org/cgi/content/full/041490898v1
1: J Infect Dis 1980 Aug;142(2):205-8
Oral transmission of kuru, Creutzfeldt-Jakob disease,
and scrapie to nonhuman primates.
Gibbs CJ Jr, Amyx HL, Bacote A, Masters CL, Gajdusek DC.
Kuru and Creutzfeldt-Jakob disease of humans and
scrapie disease of sheep and goats were transmitted to
squirrel monkeys (Saimiri sciureus) that were exposed
to the infectious agents only by their nonforced
consumption of known infectious tissues. The
asymptomatic incubation period in the one monkey
exposed to the virus of kuru was 36 months; that in the
two monkeys exposed to the virus of Creutzfeldt-Jakob
disease was 23 and 27 months, respectively; and that in
the two monkeys exposed to the virus of scrapie was 25
and 32 months, respectively. Careful physical
examination of the buccal cavities of all of the
monkeys failed to reveal signs or oral lesions. One
additional monkey similarly exposed to kuru has
remained asymptomatic during the 39 months that it has
been under observation.
PMID: 6997404
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6997404&dopt=Abstract
NOTES
Interspecies Transmission of Chronic Wasting Disease
Prions to
Squirrel Monkeys (Saimiri sciureus)
Richard F. Marsh,1? Anthony E. Kincaid,2 Richard A.
Bessen,3 and Jason C. Bartz4*
Department of Animal Health and Biomedical Sciences,
University of Wisconsin, Madison 537061; Department of
Physical Therapy2 and Department of Medical
Microbiology and Immunology,4 Creighton University, Omaha,
Nebraska 68178; and Department of Veterinary Molecular
Biology, Montana
State University, Bozeman, Montana 597183
Received 3 May 2005/Accepted 10 August 2005
Chronic wasting disease (CWD) is an emerging prion
disease of deer and elk. The risk of CWD transmission
to humans following exposure to CWD-infected tissues is
unknown. To assess the susceptibility of nonhuman
primates to CWD, two squirrel monkeys were inoculated
with brain tissue from a CWD-infected mule deer. The
CWD-inoculated squirrel monkeys developed a progressive
neurodegenerative disease and were euthanized at
31 and 34 months postinfection. Brain tissue from the
CWD-infected squirrel monkeys contained the abnormal
isoform of the prion protein, PrP-res, and displayed
spongiform degeneration. This is the first reported
transmission of CWD to primates.
snip...
JOURNAL OF VIROLOGY, Nov. 2005, p. 13794-13796 Vol.
79, No. 21
0022-538X/05/$08.00!0
doi:10.1128/JVI.79.21.13794-13796.2005
Copyright © 2005, American Society for Microbiology.
All Rights Reserved.
=============================================
Full Text
Diagnosis and Reporting of Creutzfeldt-Jakob Disease
Singeltary, Sr et al.
JAMA.2001; 285: 733-734
http://jama.ama-assn.org/cgi/content/full/285/6/733?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=dignosing+and+reporting+creutzfeldt+jakob+disease&searchid=1048865596978_1528&stored_search=&FIRSTINDEX=0&journalcode=jama
http://www.neurology.org/cgi/eletters/60/2/176#535
LANCET INFECTIOUS DISEASE JOURNAL
Volume 3, Number 8 01 August 2003
Newsdesk
Tracking spongiform encephalopathies in North America
http://infection.thelancet.com/journal/journal.isa
BMJ
http://www.bmj.com/cgi/eletters/319/7220/1312/b#EL2
BMJ
http://www.bmj.com/cgi/eletters/320/7226/8/b#EL1
TSS
mwj
Well-known member
Flounder since you have the brain plus the true answers why are you not the only source of info? I would think that every beef producing country in the world would be camped on your doorstep. You may have a lot of information but you do not have all the answers :roll: