Tuesday, December 15, 2009

Intraspecies transmission of L-type-like bovine spongiform encephalopathy detected in Japan


Intraspecies transmission of L-type-like bovine spongiform encephalopathy detected in Japan

Shigeo Fukuda 1*, Yoshifumi Iwamaru 2*, Morikazu Imamura 2 , Kentarou Masujin 2 , Yoshihisa Shimizu 2 , Yuichi Matsuura 2 , Yujing Shu 2 , Megumi Kurachi 2 , Kazuo Kasai 2 , Yuichi Murayama 2 , Sadao Onoe 1 , Ken'ichi Hagiwara 3 , Tetsutaro Sata 4 , Shirou Mohri 2 , Takashi Yokoyama 2 and Hiroyuki Okada 2 1 Molecular Biotechnology Laboratory, Hokkaido Animal Research Center, Shintoku, Hokkaido 081-0038, Japan 2 Prion Disease Research Center, National Institute of Animal Health, 3-1-5 Kan-nondai, Tsukuba, Ibaraki 305-0856, Japan 3 Departments of Biochemistry and Cell Biology , and 4 Pathology, National Institute of Infectious Diseases, Toyama 1-23-1 Shinjuku-ku, Tokyo, 162-8640, Japan Correspondence Hiroyuki Okada, Prion Disease Research Center, National Institute of Animal Health, Kannonndai 3-1-5, Tsukuba, Ibaraki 305-0856, Japan. Tel & fax: +81-29-838-7757; email: okadahi@affrc.go.jp

*These authors contributed equally to this work.

Copyright © 2009 Japanese Society for Bacteriology, Japanese Society for Virology, Japanese Society for Host Defense Research, and Blackwell Publishing Asia Pty Ltd KEYWORDS atypical bovine spongiform encephalopathy • cattle • L-type-like • transmission


It has been assumed that the agent causing BSE in cattle is a uniform strain (classical BSE); however, different neuropathological and molecular phenotypes of BSE (atypical BSE) have been recently reported. We demonstrated the successful transmission of L-type-like atypical BSE detected in Japan (BSE/JP24 isolate) to cattle. Based on the incubation period, neuropathological hallmarks, and molecular properties of the abnormal host prion protein, the characteristics of BSE/JP24 prion were apparently distinguishable from the classical BSE prion and closely resemble those of bovine amyloidotic spongiform encephalopathy prion detected in Italy.


Received 7 May 2009; revised 2 August 2009; accepted 4 August 2009.

DIGITAL OBJECT IDENTIFIER (DOI) 10.1111/j.1348-0421.2009.00169.x About DOI


In Japan, two atypical BSE cases have been identified to date. The first case showed an L-type-like electrophoretic mobility of the unglycosylated PrPSc on western blot analysis (9). The second casewas identified in an aged beef cattle, Japanese Black (BSE/JP24), and showed PrP-positive amyloid plaques in histopathological examination of the brain and a distinct glycoformprofile (10). Although such properties seem to be similar to those reported in a BASE case (7), unlike with the BASE prion, shortening of the incubation periods was observed in bovinized mice serially passaged with the BSE/JP24 prion (11). Thus, it remains controversial whether the BSE/JP24 prion is identical to the BASE prion. These observations prompted us to characterize the phenotypes of the BSE/JP24 prion propagated in its natural host by comparison with those of the classical BSE prion. Hence, we have inoculated with brain homogenates from classical BSE and BSE/JP24 isolates into Holstein cattle and assessed their risk against cattle species.


In summary, we demonstrated the successful transmission of the BSE/JP24 prion to cattle. The BSE/JP24 prion-affected cattle sustained the molecular properties of PK-treated PrPSc as those of the original BSE/JP24 isolate. Although most brain regions except for the medulla oblongata of the original BSE/JP24 isolate were unable to be investigated due to inadequate specimen collection, in comparison to experimentally BSE/JP24 prion-affected cattle, both neuropathological features, such as severe vacuolation in the medulla oblongata at the obex level and the presence of PrPSc plaques, closely resembled each other. Based on molecular properties of PK-treated PrPSc and a detailed comparison of the immunohistochemical and neuropathological properties, the BSE/JP24 prion was distinguishable from those in the classical BSE prion, and appear to be rather similar to the BASE prion (8). Of interest, experimental transmission of the BSE/JP24 prion to cattle induced a shorter incubation period and more severe neuropathological changes compared to the classical BSE prion, suggesting that the BASE and BSE/JP24 prion might be more virulent in cattle species. However, such speculation conflicts with reports that atypical BSE field cases have been mainly found in adult and aged cattle (5). The reason for this discrepancy in incubation periods between experimentally and naturally affected cattle is unknown. These observations may imply that atypical BSE are sporadic forms of BSE. Alternatively, the route of infection and/or prion titer may be attributed to the relatively long incubation period in natural atypical cases. Further studies using orally BSE/JP24 prion-affected cattle will be needed to address this issue.


>>> These observations may imply that atypical BSE are sporadic forms of BSE.

PLEASE SEE BELOW "So far, there is no evidence for spontaneous PrPSc formation in any animal or human TSE."

Prions: Protein Aggregation and Infectious Diseases


Institute of Neuropathology, University Hospital of Zurich, Zurich, Switzerland


3. Sporadic Creutzfeldt-Jakob disease Approximately 85% of all human prion diseases are sporadic forms of CJD. For sCJD, there is no association with a mutant PRNP allele, nor is there any epidemiological evidence for exposure to a TSE agent through contact with people or animals infected with TSEs. sCJD cases are currently subclassified according to the methionine/valine polymorphism at codon 129 of the PRNP gene and the size and glycoform ratio of proteaseresistant prion protein identified on western blot (type 1 or type 2) (174). Heterozygosity (Met/Val) at PrP codon 129 appears to be associated with a lower risk (378) and/or prolonged incubation time (119, 387). The lack of routine laboratory testing for preclinical diagnosis makes the search for agent sources and other risk factors extremely difficult. At present, the means of acquisition of a TSE agent in these patients remains a mystery. So far, there is no evidence for spontaneous PrPSc formation in any animal or human TSE. In humans, the peak age incidence of sporadic CJD is 55–60 years. However, if spontaneous misfolding were the primary event, one might expect a continuously increasing incidence with age because more time would allow more opportunity for rare misfolding events.


Physiol Rev • VOL 89 • OCTOBER 2009 • www.prv.org


O.11.2 Transmission of bovine-passaged TME prion strain to macaque Emmanuel Comoy1, Juergen Richt2, Valérie Durand1, Sophie Freire1, Evelyne Correia1, Amir Hamir2, Marie- Madeleine Ruchoux1, Paul Brown1, Jean-Philippe Deslys1 1Atomic Energy Commission, France; 2National Animal Disease Center, USA Background: The origin of Transmissible Mink Encephalopathy (TME) remains controversial, with historical evidence for either scrapie or BSE as the source of separate outbreaks. The case for BSE is supported by the experimental transmission of BSE from cattle to mink, whereas scrapie failed to transmit from sheep to mink. Transmission of TME from mink to cynomolgus macaque is inefficient, suggesting a low risk of TSE to human health. Because only typical and atypical BSE prion strains have been shown to be easily transmissible from non-primate to primate species, we have investigated transmissibility to monkeys of a cattle-passaged strain of TME. Objectives: To compare the transmissibility of cattle-passaged TME prions to the transmissibility of other cattle-passaged prions. Methods: Monkeys (cynomolgus macaques) were intra-cerebrally infected with classical BSE, atypical BSE strains (BASE and BSE H), and a cattle-passaged TME strain. Animals were regularly monitored for clinical signs, and extensive biochemical and immunohistochemical studies were performed on lymphoid and neural tissues of animals that have already died. Results and discussion: The animal infected with the cattlepassaged TME strain developed neurological clinical signs after a very short incubation period of 20 months, with a clinical picture that is clearly different from that of BSE/vCJD-infected animals, but similar to that of BASE (the animal is still alive at the time of this writing but post-mortem histopathological and immunohistochemical analyses will provide a more complete characterization of the disease). This new transmission reinforces the notion of human vulnerability to prion diseases passaged through cattle, perhaps due to a low species barrier.

Selected by the scientific committee from the submitted abstracts

O.11.3 Infectivity in skeletal muscle of BASE-infected cattle Silvia Suardi1, Chiara Vimercati1, Fabio Moda1, Ruggerone Margherita1, Ilaria Campagnani1, Guerino Lombardi2, Daniela Gelmetti2, Martin H. Groschup3, Anne Buschmann3, Cristina Casalone4, Maria Caramelli4, Salvatore Monaco5, Gianluigi Zanusso5, Fabrizio Tagliavini1 1Carlo Besta” Neurological Institute,Italy; 2IZS Brescia, Italy; 33FLI Insel Riems, D, Germany; 4CEA-IZS Torino, Italy; 5University of Verona, Italy Background: BASE is an atypical form of bovine spongiform encephalopathy caused by a prion strain distinct from that of BSE. Upon experimental transmission to cattle, BASE induces a previously unrecognized disease phenotype marked by mental dullness and progressive atrophy of hind limb musculature. Whether affected muscles contain infectivity is unknown. This is a critical issue since the BASE strain is readily transmissible to a variety of hosts including primates, suggesting that humans may be susceptible. Objectives: To investigate the distribution of infectivity in peripheral tissues of cattle experimentally infected with BASE. Methods: Groups of Tg mice expressing bovine PrP (Tgbov XV, n= 7-15/group) were inoculated both i.c. and i.p. with 10% homogenates of a variety of tissues including brain, spleen, cervical lymph node, kidney and skeletal muscle (m. longissimus dorsi) from cattle intracerebrally infected with BASE. No PrPres was detectable in the peripheral tissues used for inoculation either by immunohistochemistry or Western blot. Results: Mice inoculated with BASE-brain homogenates showed clinical signs of disease with incubation and survival times of 175±15 and 207±12 days. Five out of seven mice challenged with skeletal muscle developed a similar neurological disorder, with incubation and survival times of 380±11 and 410±12 days. At present (700 days after inoculation) mice challenged with the other peripheral tissues are still healthy. The neuropathological phenotype and PrPres type of the affected mice inoculated either with brain or muscle were indistinguishable and matched those of Tgbov XV mice infected with natural BASE. Discussion: Our data indicate that the skeletal muscle of cattle experimentally infected with BASE contains significant amount of infectivity, at variance with BSE-affected cattle, raising the issue of intraspecies transmission and the potential risk for humans. Experiments are in progress to assess the presence of infectivity in skeletal muscles of natural BASE.

Selected by the scientific committee from the submitted abstracts

P.9.21 Molecular characterization of BSE in Canada Jianmin Yang1, Sandor Dudas2, Catherine Graham2, Markus Czub3, Tim McAllister1, Stefanie Czub1 1Agriculture and Agri-Food Canada Research Centre, Canada; 2National and OIE BSE Reference Laboratory, Canada; 3University of Calgary, Canada Background: Three BSE types (classical and two atypical) have been identified on the basis of molecular characteristics of the misfolded protein associated with the disease. To date, each of these three types have been detected in Canadian cattle. Objectives: This study was conducted to further characterize the 16 Canadian BSE cases based on the biochemical properties of there associated PrPres. Methods: Immuno-reactivity, molecular weight, glycoform profiles and relative proteinase K sensitivity of the PrPres from each of the 16 confirmed Canadian BSE cases was determined using modified Western blot analysis. Results: Fourteen of the 16 Canadian BSE cases were C type, 1 was H type and 1 was L type. The Canadian H and L-type BSE cases exhibited size shifts and changes in glycosylation similar to other atypical BSE cases. PK digestion under mild and stringent conditions revealed a reduced protease resistance of the atypical cases compared to the C-type cases. N terminal- specific antibodies bound to PrPres from H type but not from C or L type. The C-terminal-specific antibodies resulted in a shift in the glycoform profile and detected a fourth band in the Canadian H-type BSE. Discussion: The C, L and H type BSE cases in Canada exhibit molecular characteristics similar to those described for classical and atypical BSE cases from Europe and Japan. This supports the theory that the importation of BSE contaminated feedstuff is the source of C-type BSE in Canada. It also suggests a similar cause or source for atypical BSE in these countries.

P.4.23 Transmission of atypical BSE in humanized mouse models Liuting Qing1, Wenquan Zou1, Cristina Casalone2, Martin Groschup3, Miroslaw Polak4, Maria Caramelli2, Pierluigi Gambetti1, Juergen Richt5, Qingzhong Kong1 1Case Western Reserve University, USA; 2Instituto Zooprofilattico Sperimentale, Italy; 3Friedrich-Loeffler-Institut, Germany; 4National Veterinary Research Institute, Poland; 5Kansas State University (Previously at USDA National Animal Disease Center), USA Background: Classical BSE is a world-wide prion disease in cattle, and the classical BSE strain (BSE-C) has led to over 200 cases of clinical human infection (variant CJD). Atypical BSE cases have been discovered in three continents since 2004; they include the L-type (also named BASE), the H-type, and the first reported case of naturally occurring BSE with mutated bovine PRNP (termed BSE-M). The public health risks posed by atypical BSE were largely undefined. Objectives: To investigate these atypical BSE types in terms of their transmissibility and phenotypes in humanized mice. Methods: Transgenic mice expressing human PrP were inoculated with several classical (C-type) and atypical (L-, H-, or Mtype) BSE isolates, and the transmission rate, incubation time, characteristics and distribution of PrPSc, symptoms, and histopathology were or will be examined and compared. Results: Sixty percent of BASE-inoculated humanized mice became infected with minimal spongiosis and an average incubation time of 20-22 months, whereas only one of the C-type BSE-inoculated mice developed prion disease after more than 2 years. Protease-resistant PrPSc in BASE-infected humanized Tg mouse brains was biochemically different from bovine BASE or sCJD. PrPSc was also detected in the spleen of 22% of BASE-infected humanized mice, but not in those infected with sCJD. Secondary transmission of BASE in the humanized mice led to a small reduction in incubation time. The atypical BSE-H strain is also transmissible with distinct phenotypes in the humanized mice, but no BSE-M transmission has been observed so far. Discussion: Our results demonstrate that BASE is more virulent than classical BSE, has a lymphotropic phenotype, and displays a modest transmission barrier in our humanized mice. BSE-H is also transmissible in our humanized Tg mice. The possibility of more than two atypical BSE strains will be discussed. Supported by NINDS NS052319, NIA AG14359, and NIH AI 77774.


Subject: Importation of Whole Cuts of Boneless Beef from Japan [Docket No. 05-004-1] RIN 0579-AB93 TSS SUBMISSION

Date: August 24, 2005 at 2:47 pm PST

August 24, 2005

Importation of Whole Cuts of Boneless Beef from Japan [Docket No. 05-004-1] RIN 0579-AB93 TSS SUBMISSION

Greetings APHIS ET AL,

My name is Terry S. Singeltary Sr.


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