Biological and biochemical characterization of L-type-like bovine spongiform encephalopathy (BSE) detected in Japanese black beef cattle

Abstract

A case of L-type-like atypical bovine spongiform encephalopathy was detected in 14-year-old Japanese black beef cattle (BSE/ JP24). To clarify the biological and biochemical properties of the prion in BSE/JP24, we performed a transmission study with wildtype mice and bovinized transgenic mice (TgBoPrP). The BSE/ JP24 prion was transmitted to TgBoPrP mice with the incubation period of 199.7 ± 3.4 days, which was shorter than that of classical BSE (C-BSE) (223.5 ± 13.5 days). Further, C-BSE was transmitted to wild-type mice with the incubation period of about 409 days, whereas BSE/JP24 prion inoculated mice showed no clinical signs up to 649 days. Severe vacuolation and a widespread and uniform distribution of PrP Sc were pathologically observed in the brain of BSE/JP24 prion affected TgBoPrP mice. The molecular weight and glycoform ratio of PrP Sc in BSE/JP24 were different from those in C-BSE, and PrP Sc in BSE/JP24 exhibited weaker proteinase K resistance than that in C-BSE. These findings revealed that the BSE/JP24 prion has distinct biological and biochemical properties reported for that of C-BSE. Interestingly, a shorter incubation period was observed at the subsequent passage of the BSE/JP24 prion to TgBoPrP mice (152.2 ± 3.1 days). This result implies that BSE/JP24 prion has newly emerged and showed the possibility that L-type BSE prion might be classified into multiple strains.

Proteasome Activity and Biological Properties of Normal Prion Protein: A Comparison between Young and Aged Cattle

“…It is very difficult to precisely estimate the influences of age on atypical and classical BSE cases. Atypical BSE and classical BSE display unique incubation periods, PrP res deposition patterns, and histological lesions [9,16]. However, because the onset of BSE is affected by exposure dose of BSE agent and host susceptibility, it is difficult to estimate the infection time for both classical and atypical BSE cases.…”

Comparative analysis of Japanese and foreign L-type BSE prions

“…18 Lesion profile analysis revealed that the degree of brain vacuolation due to the Japanese L-type BSE isolate was similar to that caused by the other L-type BSE isolates (Fig. 1A).…”

“…The analyses of L-type BSE cases have been performed using different bovinized PrP-overexpressing transgenic mice, such as TgBoPrP, 18 Tgbov XV 11,21 and Tg540. 22 Thus, it has been impossible to compare the properties of L-type BSE isolates in detail.…”

Examination of the Offspring of a Japanese Cow Affected with L-Type Bovine Spongiform Encephalopathy

“…Atypical BSEs are classified into 2 forms on the basis of the molecular weight of the proteinase K-resistant core fragment of the abnormal prion protein PrP Sc : L-type BSE (L-BSE) or bovine amyloidotic spongiform encephalopathy and H-type BSE (H-BSE) [3,5]. Several studies have indicated that L-BSE and H-BSE are caused by different prions with varying biological characteristics [4,11,12]. A limited number of atypical BSE cases have been reported, and sporadic occurrence may be supposed as their origin [2].…”

“…Thereafter, this case was referred as L-BSE [9]. Cattle [6] and mice overexpressing bovine PrP [12] that had been experimentally challenged with L-BSE had a shorter incubation period and exhibited more severe spongiform changes in the brain than the mice and cattle that had been experimentally challenged with C-BSE. These results suggest that the L-BSE prion exhibits greater virulence in cattle than the C-BSE prion.…”