Saturday, December 05, 2009

Molecular Model of Prion Transmission to Humans

Molecular Model of Prion Transmission to Humans

Michael Jones, Darren Wight, Rona Barron, Martin Jeffrey, Jean Manson, Christopher Prowse, James W. Ironside, and Mark W. Head

To assess interspecies barriers to transmission of transmissible spongiform encephalopathies (TSEs), we investigated the ability of disease-associated prion proteins (PrPd) to initiate conversion of the human normal cellular form of prion protein of the 3 major PRNP polymorphic variants in vitro. Protein misfolding cyclic amplifi cation showed that conformation of PrPd partly determines host susceptibility.



Our results are best appreciated in terms of the molecular interaction between seed PrPd and substrate PrPC, specifi cally the species-specifi c amino acid sequence and PRNP polymorphic status of PrPC and PrPd and the PrPd conformers involved (Table). Regardless of the seed PrP amino acid sequence, the PrPd conformers associated with bovine BSE, ovine BSE, and human vCJD were amplifi ed in the humanized mouse substrate and displayed similar PRNP-129 genotype preferences (PRNP-129MM >PRNP- 129MV >PRNP-129VV). In contrast, the PrPd conformer associated with the ovine scrapie strain, although sharing the same PrP amino acid sequence as the PrPd in ovine BSE, could not be amplifi ed in any of the PRNP humanized mouse substrates but could be amplifi ed in a sheep brain substrate. These observations are consistent with conformation of a TSE agent’s PrPd (rather than solely its amino acid sequence) having a role in determining the susceptibility of a host’s PrPC to conversion. They similarly suggest that these molecular factors could in turn have a powerful infl uence on disease susceptibility and incubation time.

To date, all clinical cases of vCJD have occurred in persons with the PRNP-129MM genotype, as might be predicted from the effi ciency of amplifi cation of BSE-related PrPd shown here. Extrapolating from these results, one would predict that the next genotypic group most likely to show susceptibility to the BSE agent would be heterozygous (MV) at codon 129 of the PRNP gene, as previously suggested from the corresponding in vivo transmission studies (14).

In the wake of BSE epidemics in the United Kingdom and elsewhere, enhanced surveillance has identifi ed apparently new TSEs (15), raising concerns regarding animal and human health. PMCA with suitable substrate sources could provide a rapid way to estimate the molecular component of transmission barriers for particular TSE agents between species, including humans. These estimates could thus indicate whether, like classical scrapie, the agents rep- resent little risk for human health or whether, like classical BSE, they represent cause for concern.


This is provided by the statistically significant increase in the incidence of sheep scrape from 1985, as determined from analyses of the submissions made to VI Centres, and from individual case and flock incident studies. ........

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.


The successful transmission of kuru, Creutzfeldt-Jakob disease, and scrapie by natural feeding to squirrel monkeys that we have reported provides further grounds for concern that scrapie-infected meat may occasionally give rise in humans to Creutzfeldt-Jakob disease.

PMID: 6997404





A The Present Position with respect to Scrapie A] The Problem

Scrapie is a natural disease of sheep and goats. It is a slow and inexorably progressive degenerative disorder of the nervous system and it ia fatal. It is enzootic in the United Kingdom but not in all countries.

The field problem has been reviewed by a MAFF working group (ARC 35/77). It is difficult to assess the incidence in Britain for a variety of reasons but the disease causes serious financial loss; it is estimated that it cost Swaledale breeders alone $l.7 M during the five years 1971-1975. A further inestimable loss arises from the closure of certain export markets, in particular those of the United States, to British sheep.

It is clear that scrapie in sheep is important commercially and for that reason alone effective measures to control it should be devised as quickly as possible.

Recently the question has again been brought up as to whether scrapie is transmissible to man. This has followed reports that the disease has been transmitted to primates. One particularly lurid speculation (Gajdusek 1977) conjectures that the agents of scrapie, kuru, Creutzfeldt-Jakob disease and transmissible encephalopathy of mink are varieties of a single "virus". The U.S. Department of Agriculture concluded that it could "no longer justify or permit scrapie-blood line and scrapie-exposed sheep and goats to be processed for human or animal food at slaughter or rendering plants" (ARC 84/77)" The problem is emphasised by the finding that some strains of scrapie produce lesions identical to the once which characterise the human dementias"

Whether true or not. the hypothesis that these agents might be transmissible to man raises two considerations. First, the safety of laboratory personnel requires prompt attention. Second, action such as the "scorched meat" policy of USDA makes the solution of the acrapie problem urgent if the sheep industry is not to suffer grievously.



Nature. 1972 Mar 10;236(5341):73-4.

Transmission of scrapie to the cynomolgus monkey (Macaca fascicularis). Gibbs CJ Jr, Gajdusek DC.

Nature 236, 73 - 74 (10 March 1972); doi:10.1038/236073a0

Transmission of Scrapie to the Cynomolgus Monkey (Macaca fascicularis)


National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, Maryland

SCRAPIE has been transmitted to the cynomolgus, or crab-eating, monkey (Macaca fascicularis) with an incubation period of more than 5 yr from the time of intracerebral inoculation of scrapie-infected mouse brain. The animal developed a chronic central nervous system degeneration, with ataxia, tremor and myoclonus with associated severe scrapie-like pathology of intensive astroglial hypertrophy and proliferation, neuronal vacuolation and status spongiosus of grey matter. The strain of scrapie virus used was the eighth passage in Swiss mice (NIH) of a Compton strain of scrapie obtained as ninth intracerebral passage of the agent in goat brain, from Dr R. L. Chandler (ARC, Compton, Berkshire).

Epidemiology of Scrapie in the United States 1977

Tuesday, April 28, 2009

Nor98-like Scrapie in the United States of America

Scrapie USA

Monday, November 30, 2009



MARCH 26, 2003

RE-Monitoring the occurrence of emerging forms of Creutzfeldt-Jakob disease in the United States

Email Terry S. Singeltary:

I lost my mother to hvCJD (Heidenhain Variant CJD). I would like to comment on the CDC's attempts to monitor the occurrence of emerging forms of CJD. Asante, Collinge et al [1] have reported that BSE transmission to the 129-methionine genotype can lead to an alternate phenotype that is indistinguishable from type 2 PrPSc, the commonest sporadic CJD. However, CJD and all human TSEs are not reportable nationally. CJD and all human TSEs must be made reportable in every state and internationally. I hope that the CDC does not continue to expect us to still believe that the 85%+ of all CJD cases which are sporadic are all spontaneous, without route/source. We have many TSEs in the USA in both animal and man. CWD in deer/elk is spreading rapidly and CWD does transmit to mink, ferret, cattle, and squirrel monkey by intracerebral inoculation. With the known incubation periods in other TSEs, oral transmission studies of CWD may take much longer. Every victim/family of CJD/TSEs should be asked about route and source of this agent. To prolong this will only spread the agent and needlessly expose others. In light of the findings of Asante and Collinge et al, there should be drastic measures to safeguard the medical and surgical arena from sporadic CJDs and all human TSEs. I only ponder how many sporadic CJDs in the USA are type 2 PrPSc?

Monitoring the occurrence of emerging forms of Creutzfeldt-Jakob disease in the United States 2003 revisited 2009

August 10, 2009


I would like to submit a review of past CJD surveillance in the USA, and the urgent need to make all human TSE in the USA a reportable disease, in every state, of every age group, and to make this mandatory immediately without further delay. The ramifications of not doing so will only allow this agent to spread further in the medical, dental, surgical arena's. North America seems to have the most species with documented Transmissible Spongiform Encephalopathy's, most all of which have been rendered and fed back to food producing animals and to humans for years. If you look at the statistics, sporadic CJD seems to be rising in the USA, and has been, with atypical cases of the sCJD. I find deeply disturbing in the year of 2009, that Human Transmissible Spongiform Encephalopathy of any strain and or phenotype, of all age groups, and I stress all age groups, because human TSE's do not know age, and they do not know borders. someone 56 years old, that has a human TSE, that has surgery, can pass this TSE agent on i.e. friendly fire, and or passing it forward, and there have been documented nvCJD in a 74 year old. Remembering also that only sporadic CJD has been documented to transmit via iatrogenic routes, until recently with the 4 cases of blood related transmission, of which the origin is thought to be nvCJD donors. However most Iatrogenic CJD cases are nothing more than sporadic CJD, until the source is proven, then it becomes Iatrogenic. An oxymoron of sorts, because all sporadic CJD is, are multiple forms, or strains, or phenotypes of Creutzfeldt Jakob Disease, that the route and source and species have not been confirmed and or documented. When will the myth of the UKBSEnvCJD only theory be put to bed for good. This theory in my opinion, and the following there from, as the GOLD STANDARD, has done nothing more than help spread this agent around the globe. Politics and money have caused the terrible consequences to date, and the fact that TSEs are a slow incubating death, but a death that is 100% certain for those that are exposed and live long enough to go clinical. once clinical, there is no recourse, to date. But, while sub-clinical, how many can one exposed human infect? Can humans exposed to CWD and scrapie strains pass it forward as some form of sporadic CJD in the surgical and medical arenas? why must we wait decades and decades to prove this point, only to expose millions needlessly, only for the sake of the industries involved? would it not have been prudent from the beginning to just include all TSE's, and rule them out from there with transmission studies and change policies there from, as opposed to doing just the opposite? The science of TSE's have been nothing more than a political circus since the beginning, and for anyone to still believe in this one strain, one group of bovines, in one geographical location, with only one age group of human TSE i.e. nvCJD myth, for anyone to believe this today only enhances to spreading of these human and animal TSE's. This is exactly why we have been in this quagmire.

The ones that believe that there is a spontaneous CJD in 85%+ of all cases of human TSE, and the ones that do not believe that cattle can have this same phenomenon, are two of the same, the industry, and so goes the political science aspect of this tobacco and or asbestos scenario i.e. follow the money. I could go into all angles of this man made nightmare, the real facts and science, for instance, the continuing rendering technology and slow cooking with low temps that brewed this stew up, and the fact that THE USA HAD THIS TECHNOLOGY FIRST AND SHIPPED IT TO THE U.K. SOME 5 YEARS BEFORE THE U.S. STARTED USING THE SAME TECHNOLOGY, to save on fuel cost. This is what supposedly amplified the TSE agent via sheep scrapie, and spread via feed in the U.K. bovine, and other countries exporting the tainted product. BUT most everyone ignores this fact, and the fact that the U.S. has been recycling more TSE, from more species with TSEs, than any other country documented, but yet, it's all spontaneous, and the rise in sporadic CJD in the U.S. is a happenstance of bad luck ??? I respectfully disagree. To top that all off, the infamous BSE-FIREWALL that the USDA always brags about was nothing more than ink on paper, and I can prove this. YOU can ignore it, but this is FACT (see source, as late as 2007, in one recall alone, some 10,000,000 MILLION POUNDS OF BANNED MAD COW FEED WENT OUT INTO COMMERCE TO BE FED OUT, and most was never recovered. This was banned blood laced, meat and bone meal. 2006 was a banner year for banned mad cow protein going into commerce in the U.S. (see source of FDA feed ban warning letter below). I stress that the August 4, 1997 USA mad cow feed ban and this infamous BSE firewall, was nothing more than ink on paper, it was never enforceable.

I propose that the current diagnostic criteria for human TSEs only enhances and helps the spreading of human TSE from the continued belief of the UKBSEnvCJD only theory in 2009. With all the science to date refuting it, to continue to validate this old myth, will only spread this TSE agent through a multitude of potential routes and sources i.e. consumption, medical i.e., surgical, blood, dental, endoscopy, optical, nutritional supplements, cosmetics etc. I propose as with Aguzzi, Asante, Collinge, Caughey, Deslys, Dormont, Gibbs, Gajdusek, Ironside, Manuelidis, Marsh, et al and many more, that the world of TSE Transmissible Spongiform Encephalopathy is far from an exact science, but there is enough proven science to date that this myth should be put to rest once and for all, and that we move forward with a new classification for human and animal TSE that would properly identify the infected species, the source species, and then the route. This would further have to be broken down to strain of species and then the route of transmission would further have to be broken down. Accumulation and Transmission are key to the threshold from sub- clinical to clinical disease, and key to all this, is to stop the amplification and transmission of this agent, the spreading of, no matter what strain. In my opinion, to continue with this myth that the U.K. strain of BSE one strain TSE in cows, and the nv/v CJD one strain TSE humans, and the one geographical location source i.e. U.K., and that all the rest of human TSE are just one single strain i.e. sporadic CJD, a happenstance of bad luck that just happens due to a twisted protein that just twisted the wrong way, IN 85%+ OF ALL HUMAN TSEs, when to date there are 6 different phenotypes of sCJD, and growing per Gambetti et al, and that no other animal TSE transmits to humans ??? With all due respect to all Scientist that believe this, I beg to differ. To continue with this masquerade will only continue to spread, expose, and kill, who knows how many more in the years and decades to come. ONE was enough for me, My Mom, hvCJD i.e. Heidenhain Variant CJD, DOD 12/14/97 confirmed, which is nothing more than another mans name added to CJD, like CJD itself, Jakob and Creutzfeldt, or Gerstmann-Straussler-Scheinker syndrome, just another CJD or human TSE, named after another human. WE are only kidding ourselves with the current diagnostic criteria for human and animal TSE, especially differentiating between the nvCJD vs the sporadic CJD strains and then the GSS strains and also the FFI fatal familial insomnia strains or the ones that mimics one or the other of those TSE? Tissue infectivity and strain typing of the many variants of the human and animal TSEs are paramount in all variants of all TSE. There must be a proper classification that will differentiate between all these human TSE in order to do this. With the CDI and other more sensitive testing coming about, I only hope that my proposal will some day be taken seriously. ...

please see history, and the ever evolving TSE science to date ;

Saturday, June 13, 2009

Monitoring the occurrence of emerging forms of Creutzfeldt-Jakob disease in the United States 2003 revisited 2009

Thursday, November 05, 2009

Incidence and spectrum of sporadic Creutzfeldt-Jakob disease variants with mixed phenotype and co-occurrence of PrPSc types: an updated classification

Tuesday, August 11, 2009

Characteristics of Established and Proposed Sporadic Creutzfeldt-Jakob Disease Variants

Brian S. Appleby, MD; Kristin K. Appleby, MD; Barbara J. Crain, MD, PhD; Chiadi U. Onyike, MD, MHS; Mitchell T. Wallin, MD, MPH; Peter V. Rabins, MD, MPH

Background: The classic Creutzfeldt-Jakob disease (CJD), Heidenhain, and Oppenheimer-Brownell variants are sporadic CJD (sCJD) phenotypes frequently described in the literature, but many cases present with neuropsychiatric symptoms, suggesting that there may be additional sCJD phenotypes.

Objective: To characterize clinical, diagnostic, and molecular features of 5 sCJD variants.

Design: Retrospective analysis.

Setting: The Johns Hopkins and Veterans Administration health care systems.

Participants: Eighty-eight patients with definite or probable sCJD.

Main Outcome Measures: Differences in age at onset, illness progression, diagnostic test results, and molecular subtype.

Results: The age at onset differed among sCJD variants (P=.03); the affective variant had the youngest mean age at onset (59.7 years). Survival time (P.001) and the time to clinical presentation (P=.003) differed among groups. Patients with the classic CJD phenotype had the shortest median survival time from symptom onset (66 days) and those who met criteria for the affective sCJD variant had the longest (421 days) and presented to clinicians significantly later (median time from onset to presentation, 92 days; P=.004). Cerebrospinal fluid analyses were positive for 14-3-3 protein in all of the affective variants, regardless of illness duration. Periodic sharp-wave complexes were not detected on any of the electroencephalography tracings in the Oppenheimer-Brownell group; basal ganglia hyperintensity was not detected on brain magnetic resonance imaging in this group either. All of the Heidenhain variants were of the methionine/ methionine type 1 molecular subtype.

Conclusions: The classic CJD phenotype and the Heidenhain, Oppenheimer-Brownell, cognitive, and affective sCJD variants differ by age at disease onset, survival time, and diagnostic test results. Characteristics of these 5 phenotypes are provided to facilitate further clinicopathologic investigation that may lead to more reliable and timely diagnoses of sCJD.

Arch Neurol. 2009;66(2):208-215



snip...see full text ;


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