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From: TSS ()
Subject: INTERVIEW - Mad Cow DNA May Offer Clues to Latest US Case
Date: June 19, 2005 at 8:31 pm PST

INTERVIEW - Mad Cow DNA May Offer Clues to Latest US Case
--------------------------------------------------------------------------------



USA: June 20, 2005

WASHINGTON - DNA from the brain of an aged beef animal could show why there were conflicting results from US mad cow tests and if the disease arose spontaneously, a British expert told Reuters on Friday.

Danny Matthews, head of the research and surveillance program for transmissible spongiform encephalopathy at the Veterinary Laboratories Agency in Weybridge, said British scientists have done similar DNA analyses on other animals.
The internationally recognized laboratory in England will carry out a series of tests on the suspect US animal, which has already undergone several with conflicting results.

While the British lab is conducting its tests, US Agriculture Department scientists will perform DNA sequencing of the prion protein from the animal's brain.

The second possible US case of mad cow disease surfaced on June 10, when it was revealed that an older animal had tested positive for the brain-wasting disease.

The question of whether mad cow disease or bovine spongiform encephalopathy (BSE) can arise spontaneously is an important one. Scientists have long believed BSE is transmitted through contaminated feed, which led to most countries banning the use of cattle remains in cattle feed.

Mad cow disease is caused by abnormal or misfolded prions in the brain.

"We have been doing ... some sequencing on the prion PRP gene, the gene that codes for producing prion protein. The hypothesis is that an abnormality in that gene could generate a spontaneous disease," Matthews said in a telephone interview.

"If anything is being done in the US on that line I suspect that is what they are looking for, to see if there's any mutation ... that might account for what they've seen."

A scientist with USDA's animal disease lab in Ames, Iowa, told Reuters this week the unusual test results could point to a new BSE strain some scientists believe occurs spontaneously.

The aging beef animal was slaughtered in November. Because it was a "downer" unable to walk, its carcass was banned from the human food supply and incinerated. If the new tests confirm infection it would be the second US case of mad cow disease.


WHAT IS 'ATYPICAL?'

Matthews said it was far from proven that atypical BSE cases mean the disease occurred spontaneously.

"Some countries have claimed that they have found something that's different. All they are seeing on the Western blot test is that the banding pattern is slightly different to a normal BSE," he said. "That is insufficient to say this is not BSE."

Many of the atypical samples found so far were in older cattle. But he cautioned that was not conclusive evidence of genetic mutation causing a spontaneous case of the infection.

Since the first confirmed US case of mad cow disease was found in December 2003, scientists in France, Italy and Japan say they have discovered different strains of BSE from the outbreak that swept European herds in the 1980s.

"The Italians published over a year ago and inoculated cattle and mice with their samples but still haven't got any evidence of transmission. France and Japan have inoculated but there are no results published so far," Matthews said.

"It may be BSE, it may be another strain of BSE or it may be something quite different which isn't even transmissible and could well be spontaneous -- but we don't know," he said.


UK TESTING FINISHED NEXT WEEK

Matthews confirmed that the brain tissue samples from the US animal had arrived at Weybridge. Test results were likely to be ready by the end of next week, he said.

The suspect animal has already undergone a series of tests. A rapid screening test on Nov. 15 returned inconclusive results. Sophisticated immunohistochemistry (IHC) tests cleared the animal of any infection, but a third round of testing using a Western blot procedure showed a "weak positive".

Weybridge will do an IHC test plus three kinds of Western Blot tests on the samples. They will use "methods of slightly different analytical sensitivity that give us the greatest number of opportunities to interpret what we see," he said.

US beef industry leaders say scientists should not speculate about the unusual case.

"There's no evidence that it's atypical ... and there's absolutely no evidence that it's spontaneous," said Gary Weber, head of regulatory affairs at the National Cattlemen's Beef Association.

Matthews noted scientists are still grappling with what is typical and atypical BSE.

"Far too few people have looked at BSE in depth using all of the tests to be able to define 'this is normal and that one isn't'," he said.

Weber noted Japan used the term to describe two very young infected cattle because BSE is usually found in older animals. Italy labeled a case "atypical" because the misshaped prions were found in unexpected parts of the animal's brain.

Story by Sophie Walker

REUTERS NEWS SERVICE

http://www.planetark.com/dailynewsstory.cfm/newsid/31303/story.htm


-------- Original Message --------
Subject: Strain-specified characteristics of mouse synthetic prions
Date: Tue, 8 Feb 2005 12:58:36 -0600
From: "Terry S. Singeltary Sr."
Reply-To: Bovine Spongiform Encephalopathy
To: BSE-L@LISTSERV.KALIV.UNI-KARLSRUHE.DE


##################### Bovine Spongiform Encephalopathy #####################

Published online before print January 25, 2005, 10.1073/pnas.0409079102
PNAS | February 8, 2005 | vol. 102 | no. 6 | 2168-2173

NEUROSCIENCE
Strain-specified characteristics of mouse synthetic prions

Giuseppe Legname *, {dagger} {ddagger} , Hoang-Oanh B. Nguyen *, Ilia
V. Baskakov * § , Fred E. Cohen *, ¶, ||, Stephen J.
DeArmond * {ddagger} , ** and Stanley B. Prusiner *, {dagger} {ddagger}
, ||, {dagger} {dagger}

*Institute for Neurodegenerative Diseases and Departments of {dagger}
Neurology, ¶Cellular and Molecular Pharmacology, ||Biochemistry and
Biophysics, and **Pathology, University of California, San Francisco, CA
94143

Contributed by Stanley B. Prusiner, December 6, 2004

Synthetic prions were produced in our laboratory by using recombinant
mouse prion protein (MoPrP) composed of residues 89-230. The first mouse
synthetic prion strain (MoSP1) was inoculated into transgenic (Tg) 9949
mice expressing N-terminally truncated MoPrP({Delta} 23-88) and WT FVB
mice expressing full-length MoPrP. On first and second passage in Tg9949
mice, MoSP1 prions caused disease in 516 ± 27 and 258 ± 25 days,
respectively; numerous, large vacuoles were found in the brainstem and
gray matter of the cerebellum. MoSP1 prions passaged in Tg9949 mice were
inoculated into FVB mice; on first and second passage, the FVB mice
exhibited incubation times of 154 ± 4 and 130 ± 3 days, respectively. In
FVB mice, vacuolation was less intense but more widely distributed, with
numerous lesions in the hippocampus and cerebellar white matter. This
constellation of widespread neuropatho-logic changes was similar to that
found in FVB mice inoculated with Rocky Mountain Laboratory (RML)
prions, a strain derived from a sheep with scrapie. Conformational
stability studies showed that the half-maximal GdnHCl (Gdn1/2)
concentration for denaturation of MoSP1 prions passaged in Tg9949 mice
was {approx} 4.2 M; passage in FVB mice reduced the Gdn1/2 value to
{approx} 1.7 M. RML prions passaged in either Tg9949 or FVB mice
exhibited Gdn1/2 values of {approx} 1.8 M. The incubation times,
neuropathological lesion profiles, and Gdn1/2 values indicate that MoSP1
prions differ from RML and many other prion strains derived from sheep
with scrapie and cattle with bovine spongiform encephalopathy.

neurodegeneration

------------------------------------------------------------------------
Author contributions: G.L., I.V.B., F.E.C., and S.B.P. designed
research; H.-O.B.N. and S.J.D. performed research; G.L., S.J.D., and
S.B.P. analyzed data; S.B.P. contributed new reagents/analytic tools;
and G.L., S.J.D., and S.B.P. wrote the paper.

Abbreviations: PrP, prion protein; MoPrP, mouse PrP; PrPSc,
disease-causing isoform of PrP; MoSP1, mouse synthetic prion1; rec,
recombinant; Tg, transgenic; RML, Rocky Mountain Laboratory; Gdn1/2,
half-maximal GdnHCl; HuM, human-mouse; PK, proteinase K.

{ddagger} G.L., S.J.D., and S.B.P. have a financial interest in InPro
Biotechnology, Inc.

§ Present address: Medical Biotechnology Center, University of Maryland
Biotechnology Institute, Baltimore, MD 21201.

{dagger} {dagger} To whom correspondence should be addressed. E-mail:
stanley@ind.ucsf.edu .

© 2005 by The National Academy of Sciences
of the USA


http://www.pnas.org/cgi/content/abstract/102/6/2168?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=prion&searchid=1107887303603_6112&stored_search=&FIRSTINDEX=0&volume=102&issue=6&journalcode=pnas


Greetings list members,


> The incubation times, neuropathological lesion profiles, and Gdn1/2
> values indicate that MoSP1 prions differ from RML and many other prion
> strains derived from sheep with scrapie and cattle with bovine
> spongiform encephalopathy.


THIS is what i was most curious about when everyone (well not everybody)
jumped on the ''spontaneous sCJD/TSE bandwagon again''. i wanted to know
if the synthetic TSE (which stan produced) was infectious. HERE we
find it is, BUT, it does not seem to match other TSEs. SO the myth
or theory that 85%+ of all sporadic CJD (or CJDs) just happen
spontaneously (without any route or source of agent) from a misfolding
prion
is pretty much put to rest. i never believed it anyway. there was never
any science
to back it up.


> SPONTANEOUS PRION DISEASES
> The discovery that a small change in the condition of a cell can cause
> the development of a prion offers an explanation, says Prusiner, for
> the sporadic form of Creutzfeldt Jakob disease (CJD), which is
> responsible for 85 percent of cases of prion disease in humans
> (occurring in 1 or 2 people per million) and is believed to develop
> spontaneously. It also supports his belief, he says, that sporadic
> forms of prion disease are caused by prion strains that are different
> from the one causing bovine spongiform encephalopathy (BSE) in cattle
> in Britain. He says he thinks that sporadic BSE will be found in one
> to five cattle per million and predicts such numbers will be found
> with increased testing for BSE.


http://www.mnbeef.org/BSE/prion_finding_offers_insight_int.htm


THIS was total BSeee and everybody knew it...

OH, and by the way, see the increase in sporadic CJD over the
last decade or so here (excluding N. America).

http://www.eurocjd.ed.ac.uk/sporadic.htm

BSE prions propagate as either variant CJD-like or sporadic CJD-like
prion strains in transgenic mice expressing human prion protein

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 1
Corresponding author e-mail: j.collinge@prion.ucl.ac.uk


Received August 1, 2002; revised September 24, 2002; accepted October
17, 2002

Abstract


Variant CreutzfeldtJakob 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
BSE-derived 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...

http://embojournal.npgjournals.com/cgi/content/full/21/23/6358

THE new findings of BASE in cattle in Italy of Identification of a
second bovine amyloidotic spongiform encephalopathy: Molecular
similarities with sporadic Creutzfeldt-Jakob disease


http://www.pnas.org/cgi/content/abstract/0305777101v1


Adaptation of the bovine spongiform encephalopathy agent to primates
and comparison with Creutzfeldt- Jakob disease: Implications for
human health

THE findings from Corinne Ida Lasmézas*, [dagger] , Jean-Guy Fournier*,
Virginie Nouvel*,

Hermann Boe*, Domíníque Marcé*, François Lamoury*, Nicolas Kopp [Dagger

] , Jean-Jacques Hauw§, James Ironside¶, Moira Bruce [||] , Dominique

Dormont*, and Jean-Philippe Deslys* et al, that 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;

http://www.pnas.org/cgi/content/full/041490898v1

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 CreutzfeldtJakob 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.

http://vir.sgmjournals.org/cgi/content/abstract/85/8/2471


REPORTS

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...

In conclusion, we have demonstrated
that BSE and vCJD prion infection in
transgenic mice can result in the propaga-
tion of distinct molecular and neuropatho-
logical phenotypes dependent on host PrP
residue 129 and possibly other, as yet
unidentified, disease modifying loci (10).
These data predict a critical role for PRNP
codon 129 in governing the thermodynamic
permissibility of human PrPSc conformation
that can be interpreted within a conforma-
tional selection model of prion transmission
barriers (17-19) (SOM text) and suggest
that there is no overlapping preferred
conformation for Val129 and Met129 human
PrP that can be generated as a result of
exposure to the vCJD/BSE prion strain.
Biophysical measurements suggest that this
powerful effect of residue 129 on prion
strain selection is likely to be mediated by
means of its effect on the conformation of
PrPSc or its precursors or on the kinetics of
their formation, as it has no measurable
effect on the folding, dynamics, or stability
of the normal cellular prion protein PrPC
(20).

Although caution must be exercised in
extrapolating from animal models, even
where, as here, faithful recapitulation of
molecular and pathological phenotypes is
possible, our findings argue that primary
human BSE prion infection, as well as sec-
ondary infection with vCJD prions by iatro-
genic routes, may not be restricted to a single
disease phenotype. These data, together with
the recent recognition of probable iatrogenic
transmission of vCJD prions to recipients of
blood {21, 22), including a PRNP codon 129
Met/Val heterozygous individual (22), re-
iterate the need to stratify all human prion
disease patients by PrPSc type. This surveil-
lance will facilitate rapid recognition of novel
PrPSc types and of any change in relative
frequencies of particular PrPSc subtypes in
relation to either BSE exposure patterns or
iatrogenic sources of vCJD prions.

References and Notes

snip...end

To whom correspondence should be addressed.
E-mail: j.collinge@prion.ucl.ac.uk

www.sciencemag.org SCIENCE VOL 306 3 DECEMBER 2004


Chronic Lymphocytic Inflammation Specifies the Organ Tropism of Prions

Mathias Heikenwalder,1* Nicolas Zeller,1* Harald Seeger,1* Marco
Prinz,1* Peter-Christian Klöhn,2 Petra
Schwarz,1 Nancy H. Ruddle,3 Charles Weissmann,2 Adriano Aguzzi1!

1Institute of Neuropathology, University Hospital of ZĂĽrich, CH-8091
ZĂĽrich, Switzerland. 2Medical Research Council Prion
Unit, Department of Neurodegenerative Diseases, Institute of Neurology,
Queen Square, London WC1N 3BG, UK. 3Department
of Epidemiology and Public Health and Section of Immunobiology, Yale
University School of Medicine, New Haven, CT
06520, USA.

*These authors contributed equally to this work.
Present address: Institute of Neuropathology, Georg-August-Universität,
D-37073 Göttingen, Germany.
!To whom correspondence should be addressed. E-mail:
adriano@pathol.unizh.ch

Prions typically accumulate in nervous and lymphoid
tissues. Because proinflammatory cytokines and immune
cells are required for lymphoid prion replication, we
tested whether inflammatory conditions affect prion
pathogenesis. We administered prions to mice with five
inflammatory diseases of kidney, pancreas or liver. In all
cases, chronic lymphocytic inflammation enabled prion
accumulation in otherwise prion-free organs.
Inflammatory foci consistently correlated with
lymphotoxin upregulation and ectopic induction of PrPCexpressing
FDC-M1+ cells, whereas inflamed organs of
mice lacking lymphotoxin-? or its receptor did not
accumulate PrPSc nor infectivity upon prion inoculation.
By expanding the tissue distribution of prions, chronic
inflammatory conditions may act as modifiers of natural
and iatrogenic prion transmission.

snip...

The above results indicate that chronic follicular
inflammation, induced by a variety of causes, specifies prion
tropism for otherwise prion-free organs. In most instances
infectivity tended to rise with time, suggesting local prion
replication. Organ-specific expression of one single proinflammatory
cytokine (LT?) or chemokine (SLC) sufficed to
establish unexpected prion reservoirs, suggesting
differentiation of ubiquitous stromal constituents into prionreplication
competent cells. In several instances, prion
concentration in individual inflamed organs approached that
of spleen long before any clinical manifestation of scrapie.
Inflamed non-lymphoid organs not only accumulated PrPSc,
but transmitted bona fide prion disease when inoculated into
healthy recipient mice.

Knowledge of the distribution of prions within infected
hosts is fundamental to consumer protection and prevention
of iatrogenic accidents. Based on the failure to transmit BSE
infectivity from any tissue but central nervous system,
intestinal, and lymphoid tissue (35), the risk to humans of
contracting prion infection from other organs has been
deemed small even in countries with endemic BSE. It may be
important now to test whether superimposed viral, microbial
or autoimmune pathologies of farm animals trigger
unexpected shifts in the organ tropism of prions. Conversely,
the lack of infectivity in burned out postinflammatory
pancreases suggests that anti-inflammatory regimens may
abolish ectopic prion reservoirs.

References and Notes ............snip...........end

/ www.sciencexpress.org / 20 January 2005 / Page 5 /
10.1126/science.1106460TSS


kind regards,
terry


######### https://listserv.kaliv.uni-karlsruhe.de/warc/bse-l.html ##########


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

Discussion

In natural and experimental TSEs, PrPSc deposition represents

an early event that occurs weeks to months before the development

of spongiform changes (20, 21). As a consequence, the

detection of PrPSc by Western immunoblot provides a unique

opportunity in the diagnosis of BSE early in the incubation

period and, therefore, in presymptomatic animals. The identification

of the present cattle by postmortem biochemical tests, in

the absence of clear neurological involvement, suggests that the

disorder was detected at early stages, and this may also explain

the lack of widespread vacuolar changes.

Previous pathological studies in clinically suspect cases of BSE

in Great Britain have provided evidence for a uniform pattern

in the severity and distribution of vacuolar lesions in affected

animals, with medulla oblongata nuclei being the most involved

(22). While confirming that the BSE epidemic has been sustained

by a single agent, these studies have assessed the validity

of statutory criteria for the diagnosis of BSE, which is currently

based on both histopathological and immunobiochemical exam-

3068  www.pnas.orgcgidoi10.1073pnas.0305777101 Casalone et al.

ination of the medulla. However, the prevailing involvement of

cortical regions in the cattle with amyloid deposition suggests

that postmortem brain sampling should not be limited to the

obex. In addition, a careful analysis of PrPSc glycoform profiles

at the confirmatory Western immunoblot may provide a molecular

means of identifying atypical cases of bovine TSE.

Bovine Amyloidotic Spongiform Encephalopathy (BASE): A Second

Bovine TSE. The present findings show that a previously undescribed

pathological and immunohistochemical phenotype, associated

with cattle TSE, is related to the presence of a PrPSc type

with biochemical properties, including the gel mobility of the

protease-resistant fragment and glycoform ratios, different from

those encountered in cattle BSE. Brain deposition of this

pathological isoform of cattle PrP correlates with the formation

of PrP-amyloid plaques, as opposed to typical BSE cases. Although

in several natural and experimental recipients of the

BSE agent, including humans (13), neuropathological changes

are characterized by the presence of PrP-positive amyloid

deposits with surrounding vacuolation, cattle BSE is not associated

with PrP-amyloid plaque formation. On the basis of the

above features, we propose to name the disease described here

BASE. Although observed in only two cattle, the BASE phenotype

could be more common than expected. In previous

studies, amyloid congophilic plaques were found in 1 of 20 BSE

cases examined systematically for amyloid (23), and it was reported

that focal cerebral amyloidosis is present in a small proportion of

BSE cases (24). Although no biochemical analysis of PrPSc glycotype

is available for these animals with ‘‘atypical BSE phenotype,’’

our present results underscore the importance of performing

a strain-typing in bovine TSE with amyloid deposition.

In sCJD, the neuropathological phenotype largely correlates

with the molecular type of PrPSc and distinct polymorphic sites

of PRNP (9, 19). This is in contrast with the situation in cattle,

where different genotypes have been reported based on the

variable numbers of octapeptide repeats in each allele, but no

evidence for single-codon polymorphisms in the PrP gene has

been established (25, 26). Because the present animals shared a

similar genetic background and breed, differences in disease

phenotypes between cattle with BSE and BASE can be tentatively

related only to distinct PrPSc types or alternative routes of

infection and spread of prion pathology. Accordingly, the lack of

involvement of the motor dorsal nucleus of the vagus and the

slight involvement of the brainstem in BASE, suggests a route for

spreading of the agent other than the alimentary tract. Therefore,

unless the BASE agent propagates throughout the olfactory

pathway or other peripheral routes, it is possible that this

disorder represents a sporadic form of cattle TSE, which would

also explain the difference in ages between the two groups of

affected animals.

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.

We are grateful to Giuseppe Ru (Centro di Referenza Nazionale per le

Encefalopatie Animali, Istituto Zooprofilattico Sperimentale di Torino)

for the provision of surveillance data. We also thank Diana Bazan for

preparing material for transmission electron microscopy, and Ines

Fig. 4. Electrophoretic analysis of PrPSc in cattle TSE and sCJD. (a) Western

blot detection of PrPSc in brains of group 1 animals (lanes 1 and 5); subject with

sCJD and type 1 PrPSc, methioninemethionine at codon 129 (lane 2); subject

with sCJD and type 2 PrPSc, methioninevaline at codon 129 (lane 3); and group

2 cattle (lane 4). (b) Relative proportions of the three PrPSc glycoforms in group

1 and group 2 cattle compared with glycoform profiles obtained in nine sCJD

patients, methioninevaline at codon 129 and with type 2 PrPSc. Mean 

standard deviation is shown. Upper band, diglycosylated form; middle band,

monoglycosylated form; and lower band, unglycosylated form.

Casalone et al. PNAS  March 2, 2004  vol. 101 

http://www.pnas.org/cgi/reprint/0305777101v1

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


MRC Prion Unit and Department of Neurodegenerative Disease, Institute of Neurology, University College, London WC1N 3BG, UK


Correspondence
John Collinge
j.collinge@prion.ucl.ac.uk

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.


http://vir.sgmjournals.org/cgi/content/abstract/85/8/2471

Asante/Collinge et al findings 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;

-------- 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)

____________________________________

snip...

full text ;

http://www.fda.gov/ohrms/dockets/ac/03/slides/3923s1_OPH.htm


Subject: Federal Veterinarian Volume 61 Number 10 October 2004 (TSE report)
Date: November 9, 2004 at 2:14 pm PST


-------- Original Message --------
Subject: Federal Veterinarian Volume 61 Number 10 October 2004 (TSE report)
Date: Tue, 9 Nov 2004 16:14:36 -0600
From: "Terry S. Singeltary Sr."
Reply-To: Bovine Spongiform Encephalopathy
To: BSE-L@UNI-KARLSRUHE.DE

snip...

http://www.vegsource.com/talk/madcow/messages/93490.html

Detecting Mad Cow Disease By Stanley B. Prusiner July 2004

http://www.google.com/search?svnum=30&as_scoring=d&hl=en&ie=UTF-8&edition=us&q=spontaneous+bse+soto+tss&as_drrb=q&as_qdr=d&btnmeta%3Dsearch%3Dsearch=Search+the+Web

-------- Original Message --------
Subject: FIVE POSSIBLE SOURCES OF BSE IN NORTH AMERICAN CATTLE
Date: Fri, 24 Sep 2004 08:58:36 -0500
From: "Terry S. Singeltary Sr."
To: Bovine Spongiform Encephalopathy


Science, Vol 305, Issue 5692, 1918-1921 , 24 September 2004
[HELP with high resolution image viewing] [Return to Article]


Five possible sources of BSE in North American cattle. Sheep, deer, and
elk could spread prion diseases (TSEs) to cattle through direct animal
contact or contamination
of pastures. Endemic BSE has not been proven to exist anywhere in the
world, but it is difficult to exclude this possibility because of the
inefficient spread of BSE infectivity
between individual animals (2). BSE caused by spontaneous misfolding of
the prion protein has not been proven.

Science, Vol 305, Issue 5692, 1918-1921 , 24 September 2004
[DOI: 10.1126/science.1103581]


BIOMEDICINE:
A Fresh Look at BSE

Bruce Chesebro*

Mad cow disease, or bovine spongiform encephalopathy (BSE), is the cattle
form of a family of progressive brain diseases. These
diseases include scrapie in sheep, Creutzfeldt-Jakob disease (CJD) in
humans, and chronic wasting disease (CWD) in deer and elk.
They are also known as either "prion diseases" because of the association
of a misfolded cellular prion protein in pathogenesis or
"transmissible spongiform encephalopathies" (TSEs) because of the
spongelike nature of the damaged brain tissue (1).

The recent discovery of two BSE-infected cows, one in Canada and one in
the United States, has dramatically increased concern in
North America among meat producers and consumers alike over the extent to
which BSE poses a threat to humans as well as to
domestic and wild animals. The European BSE epidemic of the late-1980s
seems to have been initiated a decade earlier in the United
Kingdom by changes in the production of meat and bone meal (MBM) from
rendered livestock, which led to contamination of MBM with
the BSE infectious agent. Furthermore, the fact that UK farmers fed this
rendered MBM to younger animals and that this MBM was
distributed to many countries may have contributed to the ensuing BSE
epidemic in the United Kingdom and internationally (2).

Despite extensive knowledge about the spread of BSE through contaminated
MBM, the source of BSE in Europe remains an unsolved
mystery (2). It has been proposed that BSE could be derived from a
cross-species infection, perhaps through contamination of MBM by
scrapie-infected sheep tissues (see the
figure). Alternatively, BSE may have been an endemic disease in cattle
that went unnoticed because of its low level of horizontal transmission.
Lastly, BSE might have originated
by "spontaneous" misfolding of the normal cellular prion protein into the
disease-associated abnormal isoform (3), which is postulated to be the
infectious agent or "prion."


Five possible sources
of BSE in North American cattle. Sheep, deer, and elk could spread prion
diseases
(TSEs) to cattle
through direct animal contact or contamination of pastures. Endemic BSE has
not been proven to
exist anywhere in the
world, but it is difficult to exclude this possibility because of the
inefficient spread of BSE
infectivity between
individual animals (2). BSE caused by spontaneous misfolding of the prion
protein has not been
proven.

CREDIT: KATHARINE
SUTLIFF/SCIENCE


Spontaneous protein misfolding is not a new phenomenon as proteins are
known to sometimes misfold after synthesis. Cells in turn have devised
ingenious ways to deal with this
problem. These include molecular chaperone proteins that bind to
misfolded proteins and help them to unfold, and organelles called
proteosomes that degrade misfolded or
unwanted proteins. However, although misfolded prion proteins have been
generated in test tubes as well as in cultured cells, it has been difficult
to demonstrate that such
misfolded abnormal prion proteins are infectious (4, 5). Even the most
recent data do not prove conclusively that infectivity has been generated
in vitro because misfolded
synthetic prion proteins were not able to transfer disease directly to
wild-type mice (6). To obtain infectivity and subsequent prion disease, the
misfolded proteins had to be
inoculated and incubated for 1 to 2 years in transgenic mice that
overexpressed a mutant version of the prion protein. Previous data from
this group showed that transgenic mice
expressing high amounts of prion protein developed neurological disease
without inoculation of misfolded prion protein (7). Thus, at the
biochemical level, the critical attributes
of the misfolded prion protein required for infectivity are not known,
and misfolding of prion protein alone may not be sufficient to generate an
infectious agent (8).

Nevertheless, the idea that BSE might originate due to the spontaneous
misfolding of prion proteins has received renewed interest in the wake of
reports suggesting the occurrence
of atypical BSE (9-11). These results imply that new strains of cattle
BSE might have originated separately from the main UK outbreak. Where and
how might such strains have
originated? Although such rare events cannot be studied directly, any
number of sources of the original BSE strain could also explain the
discovery of additional BSE strains in
cattle (see the figure). However, it would be worrisome if spontaneous
BSE were really a valid etiology because such a mechanism would be
impossible to prevent--unlike other
possible scenarios that could be controlled by large-scale eradication of
TSE-positive animals.

Another way to look at this problem is to examine evidence for possible
spontaneous TSE disease in other animals besides cattle. Spontaneous BSE
would be extremely difficult to
detect in cattle, where horizontal spread is minimal. However, in the
case of the sheep TSE disease, scrapie, which spreads from ewes to lambs at
birth as well as between adults,
spontaneous disease should be detectable as new foci of clinical
infection. In the early 1950s scrapie was eradicated in both Australia and
New Zealand, and the mainland of both
these countries has remained scrapie-free ever since. This scrapie-free
status is not the result of selection of sheep resistant to scrapie because
sheep from New Zealand are as
susceptible as their UK counterparts to experimental scrapie infection
(12). These experiments of man and nature appear to indicate that
spontaneous clinical scrapie does not
occur in sheep. Similarly, because CWD is known to spread horizontally,
the lack of CWD in the deer or elk of eastern North America but its
presence in western regions would
also argue against a spontaneous disease mechanism. This is particularly
noteworthy in New Zealand, where there are large numbers of deer and elk
farms and yet no evidence of
spontaneous CWD. If spontaneous scrapie does not occur in sheep or deer,
this would suggest that spontaneous forms of BSE and sporadic
Creutzfeldt-Jakob disease (sCJD) are
unlikely to be found in cattle or humans. The main caveat to this notion
is that spontaneous disease may arise in some animal species but not
others. In humans, sCJD--which is
considered by some researchers to begin by spontaneous misfolding of the
prion protein--usually takes more than 50 years to appear. Thus, in animals
with a shorter life-span,
such as sheep, deer, and cattle, an analogous disease mechanism might not
have time to develop.

What can we conclude so far about BSE in North America? Is the BSE
detected in two North American cows sporadic or spontaneous or both?
"Sporadic" pertains to the rarity of
disease occurrence. "Spontaneous" pertains to a possible mechanism of
origin of the disease. These are not equivalent terms. The rarity of BSE in
North America qualifies it as a
sporadic disease, but this low incidence does not provide information
about cause. For the two reported North American BSE cases, exposure to
contaminated MBM remains the
most likely culprit. However, other mechanisms are still possible,
including cross-infection by sheep with scrapie or cervids with CWD,
horizontal transmission from cattle
with endemic BSE, and spontaneous disease in individual cattle. Based on
our understanding of other TSEs, the spontaneous mechanism is probably the
least likely. Thus,
"idiopathic" BSE--that is, BSE of unknown etiology--might be a better
term to describe the origin of this malady.

What does all this imply about testing cattle for BSE in North America?
Current testing in the United States indicates that BSE is rare (one
positive result in 40,000 cattle
tested). However, additional testing of 200,000 head of slaughtered
cattle over the next 1 to 2 years, as recently proposed by the U.S.
Department of Agriculture (USDA), should
tell us the incidence more precisely. Nevertheless, if any rare cases are
detected, we may still not know their origin. If evidence arises of a focal
occurrence of BSE, we might
gain important insight into unexpected sources of contamination. However,
because current tests do not seem to be able to detect BSE in infected
animals less than 30 months of
age, even more extensive testing will not completely guarantee the
negative status of younger animals in the food chain. Therefore, the
alternative option of testing all slaughtered
cattle, as implemented in some countries such as Japan, would appear to
provide little additional benefit. This fact has been acknowledged as the
basis for a new agreement between
the United States and Japan aimed at reestablishing the beef trade
between the two countries.

One problem with the current U.S. testing program was the announcement a
few months ago of unconfirmed positive BSE tests in two additional North
American animals that were
subsequently found to be negative when tested with the more accurate
method of Western blotting. The public release of information about
unconfirmed positive tests detected by
the rapid test used for mass screening may be a good idea in the interest
of openness, but it has the potential to create unwarranted anxiety. If
unconfirmed positives are a
frequent occurrence, it would seem reasonable to follow a more cautious
approach and wait until confirmatory testing is complete before publicly
announcing the details.

Based on the experience of many European countries, the mainstays of
controlling BSE in cattle and avoiding spread to humans are threefold:
first, eliminate feeding of ruminant
tissues to ruminants; second, remove high-risk cattle tissues from human
food; and third, continue to test for BSE in cattle in order to monitor
progress with the elimination of
the disease on a local and national basis. In the next 12 months, after
extensive USDA test results are available, the extent of any possible BSE
spread in the United States will be
better documented. But, in fact, the United States and Canada have
already instituted the most important steps to prevent the spread of cattle
BSE in advance of the results--that
is, a ban on feeding ruminant MBM to other ruminants and removal of
high-risk tissues from meat for human consumption. It is hoped that the new
data will not deviate enough
from previous predictions to require further measures for management of
this problem. The most important line of defense against any possible
spread of BSE will be to maintain
strict vigilance in the implementation of the current regulations.

References

1.S. B. Prusiner, Proc. Natl. Acad. Sci. U.S.A 95, 13363 (1998)
[Medline].
2.P. G. Smith, R. Bradley, Br. Med. Bull. 66, 185 (2003) [Medline].
3.C. Weissmann, A. Aguzzi, Curr. Opin. Neurobiol. 7, 695 (1997)
[Medline].
4.A. F. Hill et al., J. Gen. Virol. 80, 11 (1999) [Medline].
5.R. Chiesa et al., J. Virol. 77, 7611 (2003) [Medline].
6.G. Legname et al., Science 305, 673 (2004).
7.D. Westaway et al., Cell 76, 117 (1994) [Medline].
8.B. Chesebro, Science 279, 42 (1998).
9.A. G. Biacabe et al., EMBO Rep. 5, 110 (2004) [Medline].
10.Y. Yamakawa et al., Jpn. J. Infect. Dis. 56, 221 (2003) [Medline].
11.C. Casalone et al., Proc. Natl. Acad. Sci. U.S.A. 101, 3065 (2004)
[Medline].
12.E. F. Houston et al., J. Gen. Virol. 83, 1247 (2002) [Medline].


The author is in the Laboratory of Persistent Virus Diseases, Rocky
Mountain Laboratories, National Institute of Allergy and Infectious
Diseases, Hamilton, MT 59840, USA.
E-mail: bschesebro@nih.gov 10.1126/science.1103581


Volume 305, Number 5692, Issue of 24 Sep 2004, pp. 1918-1921.
Copyright © 2004 by The American Association for the Advancement of
Science. All rights reserved.


http://www.sciencemag.org/cgi/content/full/305/5692/1918

TSS

Terry S. Singeltary Sr.




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