Monday, June 22, 2009

PrPTSE in muscle-associated lymphatic tissue during the preclinical stage of mice orally-infected with BSE

Published online ahead of print on 17 June 2009 as doi:10.1099/vir.0.010801-0 J Gen Virol (2009), DOI 10.1099/vir.0.010801-0 © 2009 Society for General Microbiology

PrPTSE in muscle-associated lymphatic tissue during the preclinical stage of mice orally-infected with BSE

Franco Cardone1,6, Achim Thomzig2, Walter J Schulz-Schaeffer3, Angelina Valanzano1, Marco Sbriccoli1, Hanin Abdel-Haq1, Silvia Graziano1, Maria Puopolo1, Paul Brown4, Michael Beekes5 and Maurizio Pocchiari1

1 Istituto Superiore di Sanità; 2 Robert Koch-Institut, Berlin, Germany; 3 Georg-August University, Goettingen, Germany; 4 None; 5 RKI

6 E-mail: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000248/!

The involvement of muscles in the pathogenesis of transmissible spongiform encephalopathies (TSE) is irregular and unpredictable. We show that the TSE-specific protein (PrPTSE) is present in muscles of mice fed with a mouse-adapted strain of bovine spongiform encephalopathy (BSE) as early as 100 days post infection, corresponding to about one third of the incubation period. The proportion of mice with positive muscles and the number of muscles involved increased as infection progressed, but never attained more than limited distribution even at the clinical stage of disease. The appearance of PrPTSE in muscles during the pre-clinical stage of disease was likely due to the haematogenous/lymphatic spread of infectivity from the gastro-intestinal tract to lymphatic tissues associated with muscles, whereas in symptomatic animals the presence of PrPTSE in the nervous system, in neuromuscular junctions, and in muscle fibers suggests a centrifugal spread from the CNS as already observed in other TSE models.

Received 4 February 2009; accepted 17 June 2009.


some past studies ;

Muscle tissue has recently been detected with PrPSc

in the peripheral nerves (sciatic nerve, tibial nerve, vagus nerve) of the 11th BSE

cow in Japan (Yoshifumi Iwamaru et al). also recently, Aguzzi et al Letter to the Editor

Vet Pathol 42:107-108 (2005), Prusiner et al CDI test is another example of detection

of the TSE agent in muscle in sCJD, Herbert Budka et al CJD and inclusion body myositis:

Abundant Disease-Associated Prion Protein in Muscle, and older studies from Watson

Meldrum et al Scrapie agent in muscle - Pattison I A (1990), references as follow ;

PrPSc distribution of a natural case of bovine

spongiform encephalopathy

Yoshifumi Iwamaru, Yuka Okubo, Tamako Ikeda, Hiroko Hayashi, Mori-

kazu Imamura, Takashi Yokoyama and Morikazu Shinagawa

Priori Disease Research Center, National Institute of Animal Health, 3-1-5

Kannondai, Tsukuba 305-0856 Japan mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000248/!


Bovine spongiform encephalopathy (BSE) is a disease of cattle that causes

progressive neurodegeneration of the central nervous system. Infectivity

of BSE agent is accompanied with an abnormal isoform of prion protein


The specified risk materials (SRM) are tissues potentially carrying BSE

infectivity. The following tissues are designated as SRM in Japan: the

skull including the brain and eyes but excluding the glossa and the masse-

ter muscle, the vertebral column excluding the vertebrae of the tail, spinal

cord, distal illeum. For a risk management step, the use of SRM in both

animal feed or human food has been prohibited. However, detailed

PrPSc distribution remains obscure in BSE cattle and it has caused con-

troversies about definitions of SRM. Therefore we have examined PrPSc

distribution in a BSE cattle by Western blotting to reassess definitions of


The 11th BSE case in Japan was detected in fallen stock surveillance.

The carcass was stocked in the refrigerator. For the detection of PrPSc,

200 mg of tissue samples were homogenized. Following collagenase

treatment, samples were digested with proteinase K. After digestion,

PrPSc was precipitated by sodium phosphotungstate (PTA). The pellets

were subjected to Western blotting using the standard procedure.

Anti-prion protein monoclonal antibody (mAb) T2 conjugated horseradish

peroxidase was used for the detection of PrPSc.

PrPSc was detected in brain, spinal cord, dorsal root ganglia, trigeminal

ganglia, sublingual ganglion, retina. In addition, PrPSc was also detected

in the peripheral nerves (sciatic nerve, tibial nerve, vagus nerve).

Our results suggest that the currently accepted definitions of SRM in

BSE cattle may need to be reexamined. ...


T. Kitamoto (Ed.)


Food and Drug Safety


ALSO from the International Symposium of Prion Diseases held in Sendai, October 31, to

November 2, 2004;

Bovine spongiform encephalopathy (BSE) in Japan


"Furthermore, current studies into transmission of cases of BSE that are

atypical or that develop in young cattle are expected to amplify the BSE


NO. Date conf. Farm Birth place and Date Age at diagnosis

8. 2003.10.6. Fukushima Tochigi 2001.10.13. 23

9. 2003.11.4. Hiroshima Hyogo 2002.1.13. 21

Test results

# 8b, 9c cows Elisa Positive, WB Positive, IHC negative, histopathology


b = atypical BSE case

c = case of BSE in a young animal

b,c, No PrPSc on IHC, and no spongiform change on histology

International Symposium of Prion Diseases held in Sendai, October 31, to

November 2, 2004.

The hardback book title is 'PRIONS' Food and Drug Safety

T. Kitamoto (Ed.)

Tetsuyuki Kitamoto

Professor and Chairman

Department of Prion Research

Tohoku University School of Medicine

2-1 SeiryoAoba-ku, Sendai 980-8575, JAPAN

TEL +81-22-717-8147 FAX +81-22-717-8148

e-mail; mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000248/!

Symposium Secretariat

Kyomi Sasaki

TEL +81-22-717-8233 FAX +81-22-717-7656

e-mail: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000248/!


Detection and Localization of PrPSc in the Skeletal Muscle

Thu Mar 2, 2006 10:40

© 2006 American Society for Investigative Pathology

Detection and Localization of PrPSc in the Skeletal Muscle of Patients with Variant, Iatrogenic, and Sporadic Forms of Creutzfeldt-Jakob Disease Alexander H. Peden, Diane L. Ritchie, Mark W. Head and James W. Ironside From the National Creutzfeldt-Jakob Disease Surveillance Unit and Division of Pathology, School of Molecular and Clinical Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom

Variant Creutzfeldt-Jakob disease (vCJD) differs from other human prion diseases in that the pathogenic prion protein PrPSc can be detected to a greater extent at extraneuronal sites throughout the body, principally within lymphoid tissues. However, a recent study using a high-sensitivity Western blotting technique revealed low levels of PrPSc in skeletal muscle from a quarter of Swiss patients with sporadic CJD (sCJD). This posed the question of whether PrPSc in muscle could also be detected in vCJD, sCJD, and iatrogenic (iCJD) patients from other populations. Therefore, we have used the same high-sensitivity Western blotting technique, in combination with paraffin-embedded tissue blotting, to screen for PrPSc in muscle tissue specimens taken at autopsy from 49 CJD patients in the United Kingdom. These techniques identified muscle PrPSc in 8 of 17 vCJD, 7 of 26 sCJD, and 2 of 5 iCJD patients. Paraffin-embedded tissue blotting analysis showed PrPSc in skeletal muscle in localized anatomical structures that had the morphological and immunohistochemical characteristics of nerve fibers. The detection of PrPSc in muscle tissue from all forms of CJD indicates the possible presence of infectivity in these tissues, suggesting important implications for assessing the potential risk of iatrogenic spread via contaminated surgical instruments.

EMBO Rep. 2003 May; 4(5): 530–533. Published online 2003 April 11. doi: 10.1038/sj.embor.embor827. PMCID: PMC1319182

Copyright © 2003, European Molecular Biology Organisation Scientific Report Widespread PrPSc accumulation in muscles of hamsters orally infected with scrapie Achim Thomzig,1 Christine Kratzel,1 Gudrun Lenz,1 Dominique Krüger,1 and Michael Beekes1a 1Robert Koch-Institut, P26, Nordufer 20, D-13353 Berlin, Germany aTel: +49 30 4547 2396; Fax: +49 30 4547 2609; Email: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000248/! Received February 13, 2003; Revised March 11, 2003; Accepted March 13, 2003. This article has been cited by other articles in PMC.

AbstractScrapie, bovine spongiform encephalopathy and chronic wasting disease are orally communicable, transmissible spongiform encephalopathies (TSEs). As zoonotic transmissions of TSE agents may pose a risk to human health, the identification of reservoirs for infectivity in animal tissues and their exclusion from human consumption has become a matter of great importance for consumer protection. In this study, a variety of muscles from hamsters that were orally challenged with scrapie was screened for the presence of a molecular marker for TSE infection, PrPSc (the pathological isoform of the prion protein PrP). Sensitive western blotting revealed consistent PrPSc accumulation in skeletal muscles from forelimb and hindlimb, head, back and shoulder, and in tongue. Previously, our animal model has provided substantial baseline information about the peripheral routing of infection in naturally occurring and orally acquired ruminant TSEs. Therefore, the findings described here highlight further the necessity to investigate thoroughly whether muscles of TSE-infected sheep, cattle, elk and deer contain infectious agent

Prions in Skeletal Muscles of Deer with Chronic Wasting Disease

Rachel C. Angers,1* Shawn R. Browning,1*† Tanya S. Seward,2 Christina J. Sigurdson,4‡ Michael W. Miller,5 Edward A. Hoover,4 Glenn C. Telling1,2,3§

1Department of Microbiology, Immunology and Molecular Genetics, 2Sanders Brown Center on Aging, 3Department of Neurology, University of Kentucky, Lexington, KY 40536, USA. 4Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA. 5Colorado Division of Wildlife, Wildlife Research Center, Fort Collins, CO 80526, USA.

*These authors contributed equally to this work.

†Present address: Department of Infectology, Scripps Research Institute, 5353 Parkside Drive, RF-2, Jupiter, Florida, 33458, USA.

‡Present address: Institute of Neuropathology, University of Zurich, Schmelzbergstrasse 12, 8091 Zurich, Switzerland.

§To whom correspondence should be addressed: E-mail: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000248/!

Prions are transmissible proteinaceous agents of mammals that cause fatal neurodegenerative diseases of the central nervous system (CNS). The presence of infectivity in skeletal muscle of experimentally infected mice raised the possibility that dietary exposure to prions might occur through meat consumption (1). Chronic wasting disease (CWD), an enigmatic and contagious prion disease of North American cervids, is of particular concern. The emergence of CWD in an increasingly wide geographic area and the interspecies transmission of bovine spongiform encephalopathy (BSE) to humans as variant Creutzfeldt Jakob disease (vCJD) have raised concerns about zoonotic transmission of CWD.

To test whether skeletal muscle of diseased cervids contained prion infectivity, Tg(CerPrP)1536 mice (2) expressing cervid prion protein (CerPrP), were inoculated intracerebrally with extracts prepared from the semitendinosus/semimembranosus muscle group of CWD-affected mule deer or from CWD-negative deer. The availability of CNS materials also afforded direct comparisons of prion infectivity in skeletal muscle and brain. All skeletal muscle extracts from CWD-affected deer induced progressive neurological dysfunction in Tg(CerPrP)1536 mice with mean incubation times ranging between 360 and ~490 d, whereas the incubation times of prions from the CNS ranged from ~230 to 280 d (Table 1). For each inoculation group, the diagnosis of prion disease was confirmed by the presence of PrPSc in the brains of multiple infected Tg(CerPrP)1536 mice (see supporting online material for examples). In contrast, skeletal muscle and brain material from CWD-negative deer failed to induce disease in Tg(CerPrP)1536 mice (Table 1) and PrPSc was not detected in the brains of sacrificed asymptomatic mice as late as 523 d after inoculation (supporting online material).

Our results show that skeletal muscle as well as CNS tissue of deer with CWD contains infectious prions. Similar analyses of skeletal muscle BSE-affected cattle did not reveal high levels of prion infectivity (3). It will be important to assess the cellular location of PrPSc in muscle. Notably, while PrPSc has been detected in muscles of scrapie-affected sheep (4), previous studies failed to detect PrPSc by immunohistochemical analysis of skeletal muscle from deer with natural or experimental CWD (5, 6). Since the time of disease onset is inversely proportional to prion dose (7), the longer incubation times of prions from skeletal muscle extracts compared to matched brain samples indicated that prion titers were lower in muscle than in CNS where infectivity titers are known to reach high levels. Although possible effects of CWD strains or strain mixtures on these incubation times cannot be excluded, the variable 360 to ~490 d incubation times suggested a range of prion titers in skeletal muscles of CWD-affected deer. Muscle prion titers at the high end of the range produced the fastest incubation times that were ~30% longer than the incubation times of prions from the CNS of the same animal. Since all mice in each inoculation group developed disease, prion titers in muscle samples producing the longest incubation times were higher than the end point of the bioassay, defined as the infectious dose at which half the inoculated mice develop disease. Studies are in progress to accurately assess prion titers.

While the risk of exposure to CWD infectivity following consumption of prions in muscle is mitigated by relatively inefficient prion transmission via the oral route (8), these

results show that semitendinosus/semimembranosus muscle, which is likely to be consumed by humans, is a significant source of prion infectivity. Humans consuming or handling meat from CWD-infected deer are therefore at risk to prion exposure.

References and Notes

1. P. J. Bosque et al., Proc. Natl. Acad. Sci. U.S.A. 99, 3812 (2002).

2. S. R. Browning et al., J. Virol. 78, 13345 (2004).

3. A. Buschmann, M. H. Groschup, J. Infect. Dis. 192, 934 (2005).

4. O. Andreoletti et al., Nat. Med. 10, 591 (2004).

5. T. R. Spraker et al., Vet. Pathol. 39, 110 (2002).

6. A. N. Hamir, J. M. Miller, R. C. Cutlip, Vet. Pathol. 41, 78 (2004).

7. S. B. Prusiner et al., Biochemistry 21, 4883 (1980).

8. M. Prinz et al., Am. J. Pathol. 162, 1103 (2003).

9. This work was supported by grants from the U.S. Public Health Service 2RO1 NS040334-04 from the National Institute of Neurological Disorders and Stroke and N01-AI-25491 from the National Institute of Allergy and Infectious Diseases.

Supporting Online Material

Materials and Methods

Fig. S1

21 November 2005; accepted 13 January 2006 Published online 26 January 2006; 10.1126/science.1122864 Include this information when citing this paper.

Table 1. Incubation times following inoculation of Tg(CerPrP)1536 mice with prions from skeletal muscle and brain samples of CWD-affected deer.

Inocula Incubation time, mean d ± SEM (n/n0)*

Skeletal muscle Brain

CWD-affected deer

H92 360 ± 2 d (6/6) 283 ± 7 d (6/6)

33968 367 ± 9 d (8/8) 278 ± 11 d (6/6)

5941 427 ± 18 d (7/7)

D10 483 ± 8 d (8/8) 231 ± 17 d (7/7)

D08 492 ± 4 d (7/7)

Averages 426 d 264 d

Non-diseased deer

FPS 6.98 >523 d (0/6)

FPS 9.98 >454 d (0/7) >454 d (0/6)

None >490 d (0/6)

PBS >589 d (0/5)

*The number of mice developing prion disease divided by the original number of inoculated mice is shown in parentheses. Mice dying of intercurrent illnesses were excluded.

Supporting Online Material for

Prions in Skeletal Muscles of Deer with Chronic Wasting Disease

Rachel C. Angers, Shawn R. Browning, Tanya S. Seward, Christina J. Sigurdson,

Michael W. Miller, Edward A. Hoover, Glenn C. Telling§

§To whom correspondence should be addressed: E-mail: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000248/!

Published 26 January 2006 on Science Express

DOI: 10.1126/science.1122864

This PDF file includes:

Materials and Methods

Fig. S1

Supporting Online Materials

Materials and Methods

Homogenates of semitendinosus/semimembranosus muscle (10% w/v in phosphate

buffered saline) were prepared from five emaciated and somnolent mule deer, naturally

infected with CWD at the Colorado Division of Wildlife, Wildlife Research Center.

These deer were identified as D10, D08, 33968, H92, and 5941. CWD infection was

confirmed in all cases by the presence of histologic lesions in the brain including

spongiform degeneration of the perikaryon, the immunohistochemical detection of

disease-associated PrP in brain and tonsil, or by immunoblotting of protease-resistant,

disease associated PrP (CerPrPSc). Semitendinosus/semimembranosus muscle was also

obtained from two asymptomatic, mock inoculated deer, referred to as FPS 6.68 and 9.98,

that originated from a CWD non-endemic area and which were held indoors at Colorado

State University from ten days of age. These control deer were confirmed negative for

CWD by histopathological and immunohistochemical analysis of brain tissue at autopsy.

The utmost care was taken to avoid inclusion of obvious nervous tissue when muscle

biopsies were prepared and to ensure that contamination of skeletal muscle samples with

CNS tissue did not occur. Fresh, single-use instruments were used to collect each sample

biopsy and a central piece from each sample was prepared with fresh, disposable

instruments to further isolate muscle tissue for inoculum preparation. Brain samples for

transmission were prepared separately from muscle as additional insurance against cross



Groups of anesthetized Tg(CerPrP)1536 mice were inoculated intracerebrally with 30 µl

of 1 % skeletal muscle or brain extracts prepared in phosphate buffered saline (PBS).

Inoculated Tg(CerPrP) mice were diagnosed with prion disease following the progressive

development of at least three neurologic symptoms including truncal ataxia, 'plastic' tail,

loss of extensor reflex, difficultly righting, and slowed movement. The time from

inoculation to the onset of clinical signs is referred to as the incubation time.

For PrP analysis in brain extracts of Tg(CerPrP)1536 mice, 10 % homogenates prepared

in PBS were either untreated (-) or treated (+) with 40 µg/ml proteinase K (PK) for one

hour at 37oC in the presence of 2% sarkosyl. Proteins were separated by sodium dodecyl

sulfate polyacrylamide gel electrophoresis, analyzed by immunoblotting using anti PrP

monoclonal antibody 6H4 (Prionics AG, Switzerland), incubated with appropriate

secondary antibody, developed using ECL-plus detection (Amersham), and analyzed

using a FLA-5000 scanner (Fuji).


Fig. S1

PrP in brain extracts from representative Tg(CerPrP)1536 mice receiving muscle or CNS

tissue inocula from CWD-affected or CWD-negative deer. Extracts were either treated

(+) or untreated (-) with proteinase K (PK) as indicated. The positions of protein

molecular weight markers at 21.3, 28.7, 33.5 kDa (from bottom to top) are shown to the

left of the immunoblot.


Prions in skeletal muscle

Patrick J. Bosque*,dagger ,Dagger , Chongsuk Ryou*, Glenn Telling*,§, David Peretz*,dagger , Giuseppe Legname*,dagger , Stephen J. DeArmond*,dagger ,¶, and Stanley B. Prusiner*,dagger ,,**

* Institute for Neurodegenerative Diseases and Departments of dagger Neurology, ¶ Pathology, and Biochemistry and Biophysics, University of California, San Francisco, CA 94143

Contributed by Stanley B. Prusiner, December 28, 2001

Considerable evidence argues that consumption of beef products from cattle infected with bovine spongiform encephalopathy (BSE) prions causes new variant Creutzfeldt-Jakob disease. In an effort to prevent new variant Creutzfeldt-Jakob disease, certain "specified offals," including neural and lymphatic tissues, thought to contain high titers of prions have been excluded from foods destined for human consumption [Phillips, N. A., Bridgeman, J. & Ferguson-Smith, M. (2000) in The BSE Inquiry (Stationery Office, London), Vol. 6, pp. 413-451]. Here we report that mouse skeletal muscle can propagate prions and accumulate substantial titers of these pathogens. We found both high prion titers and the disease-causing isoform of the prion protein (PrPSc) in the skeletal muscle of wild-type mice inoculated with either the Me7 o Rocky Mountain Laboratory strain of murine prions. Particular muscles accumulated distinct levels of PrPSc, with the highest levels observed in muscle from the hind limb. To determine whether prions are produced or merely accumulate intramuscularly, we established transgenic mice expressing either mouse or Syrian hamster PrP exclusively in muscle. Inoculating these mice intramuscularly with prions resulted in the formation of high titers of nascent prions in muscle. In contrast, inoculating mice in which PrP expression was targeted to hepatocytes resulted in low prion titers. Our data demonstrate that factors in addition to the amount of PrP expressed determine the tropism of prions for certain tissues. That some muscles are intrinsically capable of accumulating substantial titers of prions is of particular concern. Because significant dietary exposure to prions might occur through the consumption of meat, even if it is largely free of neural and lymphatic tissue, a comprehensive effort to map the distribution of prions in the muscle of infected livestock is needed. Furthermore, muscle may provide a readily biopsied tissue from which to diagnose prion disease in asymptomatic animals and even humans. Dagger Present address: Department of Medicine, Denver Health Medical Center, Denver, CO 80204.

§ Present address: Department of Microbiology and Immunology, University of Kentucky, Lexington, KY 40536-0230.

** To whom reprint requests should be addressed. E-mail: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000248/!

Extraneural Pathologic Prion Protein in Sporadic Creutzfeldt-Jakob Disease

Markus Glatzel, M.D., Eugenio Abela, Manuela Maissen, M.S., and Adriano Aguzzi, M.D., Ph.D.


Conclusions Using sensitive techniques, we identified extraneural deposition of PrPSc in spleen and muscle samples from approximately one third of patients who died with sporadic Creutzfeldt-Jakob disease. Extraneural PrPSc appears to correlate with a long duration of disease.

EMBO reports AOP Published online: 11 April 2003

Widespread PrPSc accumulation in muscles of hamsters orally infected with scrapie

Achim Thomzig, Christine Kratzel, Gudrun Lenz, Dominique KrÒ¼ger & Michael Beekes Robert Koch-Institut, P26, Nordufer 20, D-13353 Berlin, Germany

Received 13 February 2003; Accepted 13 March 2003; Published online 11 April 2003.

Abstract :

Scrapie, bovine spongiform encephalopathy and chronic wasting disease are orally communicable, transmissible spongiform encephalopathies (TSEs). As zoonotic transmissions of TSE agents may pose a risk to human health, the identification of reservoirs for infectivity in animal tissues and their exclusion from human consumption has become a matter of great importance for consumer protection. In this study, a variety of muscles from hamsters that were orally challenged with scrapie was screened for the presence of a molecular marker for TSE infection, PrPSc (the pathological isoform of the prion protein PrP). Sensitive western blotting revealed consistent PrPSc accumulation in skeletal muscles from forelimb and hindlimb, head, back and shoulder, and in tongue. Previously, our animal model has provided substantial baseline information about the peripheral routing of infection in naturally occurring and orally acquired ruminant TSEs. Therefore, the findings described here highlight further the necessity to investigate thoroughly whether muscles of TSE-infected sheep, cattle, elk and deer contain infectious agents.

Detection of Prion Infectivity in Fat Tissues of Scrapie-Infected Mice

Brent Race1#, Kimberly Meade-White1#, Michael B. A. Oldstone2, Richard Race1, Bruce Chesebro1*

1 Laboratory of Persistent Virus Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America, 2 Department of Immunology and Microbial Science, The Scripps Research Institute, LaJolla, California, United States of America

Abstract Distribution of prion infectivity in organs and tissues is important in understanding prion disease pathogenesis and designing strategies to prevent prion infection in animals and humans. Transmission of prion disease from cattle to humans resulted in banning human consumption of ruminant nervous system and certain other tissues. In the present study, we surveyed tissue distribution of prion infectivity in mice with prion disease. We show for the first time detection of infectivity in white and brown fat. Since high amounts of ruminant fat are consumed by humans and also incorporated into animal feed, fat-containing tissues may pose a previously unappreciated hazard for spread of prion infection.

Author Summary Prion diseases, also known as transmissible spongiform encephalopathies, are infectious progressive fatal neurodegenerative diseases which affect humans as well as wild and domestic animals. Distribution of prion infectivity in organs and tissues is important in understanding prion disease pathogenesis and designing strategies to prevent prion infection in animals and humans. We show for the first time the presence of prion infectivity in white fat and brown fat tissues of mice with prion disease. Our results suggest that fat tissues of domestic or wild animals infected with prions may pose an unappreciated hazard for spread of infection to humans or domestic animals. The presence of prion infectivity in fat suggests that additional consideration may be required to eliminate from the food chain any fat from ruminants suspected of exposure to or infection with prions. Thus, this finding has implications for public health, food safety, and prion disease prevention strategies.

Citation: Race B, Meade-White K, Oldstone MBA, Race R, Chesebro B (2008) Detection of Prion Infectivity in Fat Tissues of Scrapie-Infected Mice. PLoS Pathog 4(12): e1000232. doi:10.1371/journal.ppat.1000232

Editor: Neil Mabbott, University of Edinburgh, United Kingdom

Received: August 12, 2008; Accepted: November 5, 2008; Published: December 5, 2008

This is an open-access article distributed under the terms of the Creative Commons Public Domain declaration which stipulates that, once placed in the public domain, this work may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose.

Funding: This research was supported in part by the Intramural Research Program of the NIH, NIAID. MBAO was funded through NIA grant AG04032.

Competing interests: The authors have declared that no competing interests exist.

* E-mail: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000248/!

# These authors contributed equally to this work.



Discussion The present results indicate that white fat and brown fat are possible tissue sources of prion infectivity which might play a role in transmission of prion disease. In vivo brown fat has a limited distribution, usually found in young animals in the intrascapular region and around various organs such as heart and kidney. In adult ruminants brown fat is minimal. Therefore, brown fat from infected animals is unlikely to be consumed by humans in large amounts. In contrast, humans often consume large amounts of ruminant white fat. In premium cuts of meat containing mostly skeletal muscle, white fat is often intertwined with muscle cells, and it is impossible to separate the two cell types. However, white fat, free of muscle, is found in subcutaneous, retroperitoneal, intraperitoneal, perirenal and other regions. Such fat is used in many processed meat products such as sausages and canned meats, and is also used in animal feeds. Our present data show clearly that fat in the absence of muscle has significant infectivity titers, which are similar to titers in muscle containing fat (Table 1). Since our skeletal muscle samples are unavoidably contaminated by white fat, it is possible that fat might be a contributor to the infectivity found in muscle. In support of this possibility we found PrPres detectable by IHC at high levels in white fat associated with skeletal muscle in some tg44 mice (Figure 4). In contrast, other groups did not mention seeing PrPres in muscle-associated fat tissue in animals where myocytes themselves were seen to be positive by IHC [13]-[20].


It is unclear why there is accumulation of PrPres and infectivity in adipose tissues. One possibility might be the high level of innervation by the autonomic nervous system in both brown and white fat. In WT mice, nerves should express cell membrane anchored PrPC (PrPsen). Sympathetic nerves have been previously implicated in transfer of scrapie infectivity from spleen to brain in mice [29], and they might also play a role in infection of fat in WT mice. In tg44 mice the mechanism of fat infection is likely to be different as there is no anchored PrPsen on the nerves. We currently postulate a role for connective tissue structures in this process.

Infectivity in fat might also contribute to environmental contamination following the death of prion infected animals. Although infectivity titers are lower in fat and muscle than in CNS, the large mass of fat and muscle makes the total infectivity from these sources similar. Furthermore, fat and muscle are readily accessible to the environment after death, whereas the CNS is highly confined in skull and vertebral column. These factors might increase the importance of fat and muscle as sources of spread of prion disease among animals.

The low or negative plasma titers found in tg44 and WT mice indicate that residual plasma cannot account for the high infectivity levels seen in fat and other tissues (Table 1). However, low levels of plasma or blood-borne infectivity might still be a mechanism for spread of infectivity among tissues in tg44 mice and possibly also WT mice. Similarly transmission of low level blood prion infectivity has been documented by blood transfusion in BSE-infected sheep [30], and also accounts for some rare cases of human variant CJD [31],[32].

In this study extraneural infection was much higher in tg44 mice expressing anchorless PrP than in WT mice. The explanation of this finding is unclear. Possibly soluble anchorless PrP facilitates spread of infection from CNS to extraneural sites by blood, lymph or nerve-mediated transport. Alternatively, the long asymptomatic survival time of tg44 mice might also contribute to high level extraneural infection. This could also be a factor in many animal prion diseases where the time course is long, i.e. 2-5 years or more, and might allow higher extraneural infectivity in fat tissues [7], [33]-[35].

The present data using a mouse model shows the proof of principle that brown and white fat tissues can be important sites of prion agent deposition. It will be important to extend these studies in the future to prion infected large animals such as cattle, sheep and cervids where there may be greater potential for contamination of human or domestic animal food chains. We are currently doing this experiment with fat from CWD deer; however, it will require an additional year to gather this data, and this result is therefore beyond the scope of the present paper. Such studies may be difficult because of the lower titers seen in these large animals compared to rodent scrapie models. For example, we often detect titers of 9-10 logID50/gram of mouse brain, whereas in brain from BSE cattle [8], and scrapie sheep [4] titers reported are 7-8 logID50/gram. We are finding similar low titers in CWD cervid brain in our deer PrP transgenic mice (unpublished data). These results could indicate either that the amount of prion agent present in ruminant brain is lower than in mice and hamsters or that the cattle, sheep and deer PrP transgenic mice used for infectivity assays are less sensitive than the WT mice or hamster PrP transgenic mice used for rodent scrapie. In either case this might affect ability to detect infectivity in fat of these important large animal models.

Materials and Methods

snip...full text ;

Research Project: Study of Atypical Bse Location: Virus and Prion Diseases of Livestock

Project Number: 3625-32000-086-05 Project Type: Specific Cooperative Agreement

Start Date: Sep 15, 2004 End Date: Sep 14, 2009

Objective: The objective of this cooperative research project with Dr. Maria Caramelli from the Italian BSE Reference Laboratory in Turin, Italy, is to conduct comparative studies with the U.S. bovine spongiform encephalopathy (BSE) isolate and the atypical BSE isolates identified in Italy. The studies will cover the following areas: 1. Evaluation of present diagnostics tools used in the U.S. for the detection of atypical BSE cases. 2. Molecular comparison of the U.S. BSE isolate and other typical BSE isolates with atypical BSE cases. 3. Studies on transmissibility and tissue distribution of atypical BSE isolates in cattle and other species.

Approach: This project will be done as a Specific Cooperative Agreement with the Italian BSE Reference Laboratory, Istituto Zooprofilattico Sperimentale del Piemonte, in Turin, Italy. It is essential for the U.S. BSE surveillance program to analyze the effectiveness of the U.S diagnostic tools for detection of atypical cases of BSE. Molecular comparisons of the U.S. BSE isolate with atypical BSE isolates will provide further characterization of the U.S. BSE isolate. Transmission studies are already underway using brain homogenates from atypical BSE cases into mice, cattle and sheep. It will be critical to see whether the atypical BSE isolates behave similarly to typical BSE isolates in terms of transmissibility and disease pathogenesis. If transmission occurs, tissue distribution comparisons will be made between cattle infected with the atypical BSE isolate and the U.S. BSE isolate. Differences in tissue distribution could require new regulations regarding specific risk material (SRM) removal.

----- Original Message -----

From: Terry S. Singeltary Sr. To: mhtml:%7B33B38F65-8D2E-434D-8F9B-8BDCD77D3066%7Dmid://00000248/!

Sent: Monday, June 15, 2009 4:30 PM

Subject: re-Research Project: Study of Atypical Bse

re-Research Project: Study of Atypical Bse

Greetings Sir,

I have been most interested in these transmission studies, and i know it is probably to early for you to say much about them. but, could you please give me an update of some kind, as to if transmission of any type occured, with any tissues and or body fluids. i suppose i am a bit anxious about these studies. ...

many thanks for your work,

kindest regards, terry



Monday, June 01, 2009

Biochemical typing of pathological prion protein in aging cattle with BSE

Sunday, June 07, 2009


Sunday, May 10, 2009

Identification and characterization of bovine spongiform encephalopathy cases diagnosed and NOT diagnosed in the United States

Sunday, December 28, 2008

MAD COW DISEASE USA DECEMBER 28, 2008 an 8 year review of a failed and flawed policy

Wednesday, August 20, 2008

Bovine Spongiform Encephalopathy Mad Cow Disease typical and atypical strains, was there a cover-up ?

Saturday, February 28, 2009

NEW RESULTS ON IDIOPATHIC BRAINSTEM NEURONAL CHROMATOLYSIS "All of the 15 cattle tested showed that the brains had abnormally accumulated PrP" 2009 SEAC 102/2

Saturday, June 13, 2009

BSE FEED VIOLATIONS USA UPDATE From 01/01/2009 To 06/10/2009

Thursday, March 19, 2009



Saturday, May 2, 2009


Sunday, April 12, 2009

BSE MAD COW TESTING USA 2009 FIGURES Month Number of Tests

Feb 2009 -- 1,891

Jan 2009 -- 4,620


Monday, May 4, 2009

Back to the Past With New TSE Testing Agricultural Research/May-June 2009

Thursday, April 9, 2009

Docket No. FDA2002N0031 (formerly Docket No. 2002N0273) RIN 0910AF46 Substances Prohibited From Use in Animal Food or Feed; Final Rule: Proposed

Sunday, April 12, 2009

r-calf and the USA mad cow problem, don't look, don't find, and then blame Canada

Sunday, May 10, 2009

Meeting of the Transmissible Spongiform Encephalopathies Committee On June 12, 2009 (Singeltary submission)

Saturday, June 13, 2009

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





This transcripts has not been edited or corrected, but appears as received from the commercial transcribing service. Accordingly, the food and Drug Administration makes no representation as to its accuracy.

Meeting of:




September 18, 2006

There is a growing number of human CJD cases, and they were presented last week in San Francisco by Luigi Gambatti(?) from his CJD surveillance collection.

He estimates that it may be up to 14 or 15 persons which display selectively SPRPSC and practically no detected RPRPSC proteins.


I ask Professor Kong ;

Thursday, December 04, 2008 3:37 PM Subject: RE: re--Chronic Wating Disease (CWD) and Bovine Spongiform Encephalopathies (BSE): Public Health Risk Assessment

''IS the h-BSE more virulent than typical BSE as well, or the same as cBSE, or less virulent than cBSE? just curious.....''

Professor Kong reply ;


''As to the H-BSE, we do not have sufficient data to say one way or another, but we have found that H-BSE can infect humans. I hope we could publish these data once the study is complete. Thanks for your interest.''

Best regards, Qingzhong Kong, PhD Associate Professor Department of Pathology Case Western Reserve University Cleveland, OH 44106 USA


I look forward to further transmission studies, and a true ENHANCED BSE/atypical BSE surveillance program put forth testing all cattle for human and animal consumption for 5 years. a surveillance program that uses the most sensitive TSE testing, and has the personnel that knows how to use them, and can be trusted. I look forward to a stringent mad cow feed ban being put forth, and then strictly enforced. we need a forced, not voluntary feed ban, an enhanced feed ban at that, especially excluding blood. we need some sort of animal traceability. no more excuses about privacy. if somebody is putting out a product that is killing folks and or has the potential to kill you, then everybody needs to know who they are, and where that product came from. same with hospitals, i think medical incidents in all states should be recorded, and made public, when it comes to something like a potential accidental transmission exposure event. so if someone is out there looking at a place to go have surgery done, if you have several hospitals having these type 'accidental exposure events', than you can go some place else. it only makes sense. somewhere along the road, the consumer lost control, and just had to take whatever they were given, and then charged these astronomical prices. some where along the line the consumer just lost interest, especially on a long incubating disease such as mad cow disease i.e. Transmissible Spongiform Encephalopathy. like i said before, there is much more to the mad cow story than bovines and eating a hamburger, we must start focusing on all TSE in all species. ...TSS

snip... SEE FULL TEXT ;

Sunday, May 10, 2009

Meeting of the Transmissible Spongiform Encephalopathies Committee On June 12, 2009 (Singeltary submission)

ALL Human and Animal Transmissible Spongiform Encephalopathy, of all phenotypes, of ALL ages, in EVERY State and INTERNATIONALLY, should be made MANDATORY reportable ASAP. ...

Terry S. Singeltary Sr. P.O. Box 42 Bacliff, Texas USA 77518

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