Analysis of atypical BSE prions propagation in bovine prion protein overexpression mice

在使用牛PrP过表达小鼠的L-BSE和H-BSE接种的时间过程研究中，在接种后60-70天后首次检测到PrPSc。孵育时间短的L-BSE感染小鼠的PrPSc蓄积量约为孵育时间长的H-BSE感染小鼠的18倍。但在疾病末期，它们的感染性滴度相似。使用野生型小鼠接种小鼠适应性BSE脑匀浆（mBSE-BH）的动力学研究表明，感染性和PrPSc积累之间的差异。通过20 K xg离心沉淀粗mBSE-BH中约99%的PrPSc。然而，在上清液（20 K-supe）中回收了约63%的感染性。有趣的是，20 K-supe接种小鼠的潜伏期明显长于mBSE-BH粗品接种小鼠的潜伏期。这些结果表明，不同类型的PrPSc可能分别在mBSE的感染性和疾病状态中起重要作用。

In time course study of L-BSE and H-BSE inoculation using bovine PrP overexpression mice, PrPSc was first detectable after 60-70 days post inoculation. L-BSE affected mice with a short incubation time accumulated approximately 18-fold higher PrPSc than H-BSE affected mice with a long incubation time. However, they had similar infectious titer at terminal stage of illness. The kinetics study using wild-type mice inoculated with mouse-adapted BSE brain homogenate (mBSE-BH) showed the discrepancy between the infectivity and PrPSc accumulation. Approximately 99% of PrPSc in crude mBSE-BH was precipitated by 20K xg centrifugation. Nevertheless, approximately 63% of infectivity was recovered in the supernatant (20K-supe). Interestingly, the incubation time of mice inoculated with 20K-supe was significantly longer than that of mice inoculated with crude mBSE-BH.These results indicate that different types of PrPSc may play important roles in mBSE infectivity and disease state, respectively.