On the basis of the biological, neuropathological, and biochemical characteristics of BSE cases, it is believed that the bovine spongiform encephalopathy (BSE) agent is a single strain (classical BSE). However, since 2003, different neuropathological and molecular phenotypes of BSE (atypical BSEs) have been reported from various countries. At present, atypical BSEs are characterized by a higher or lower molecular mass of the unglycosylated form of the disease-associated prion protein than that of classical BSE and referred to as H-type or L-type BSE, respectively. In Japan, 2 cases of atypical BSE have been identified; the second case was identified in aged beef cattle (BSE/JP24). To characterize the phenotypes of the BSE/JP24 prion propagated in its natural host, a transmission study with cattle was performed. We demonstrated the successful transmission of the BSE/JP24 prion to cattle. On the basis of the incubation period, neuropathological hallmarks, and molecular properties of the abnormal host prion protein, the characteristics of BSE/JP24 prion were apparently distinguishable from that of the classical BSE prion, and they closely resembled those of the L-type BSE found in Italy.
(Research Team for Prion Diseases, TEL +81-29-838-7708)
Reference:
Fukuda, S., Iwamaru, Y. et al. (2009) Microbiol. Immunol. 53:704-707.