Agence Française de Sécurité Sanitaire des Aliments-Lyon, Lyon, France.
PLoS One. 2011 Jan 14;6(1):e15839. doi: 10.1371/journal.pone.0015839.
Two distinct forms of atypical spongiform encephalopathies (H-BSE and L-BSE) have recently been identified in cattle. Transmission studies in several wild-type or transgenic mouse models showed that these forms were associated with two distinct major strains of infectious agents, which also differed from the unique strain that had been isolated from cases of classical BSE during the food-borne epizootic disease.
METHODOLOGY/PRINCIPAL FINDINGS: H-BSE was monitored during three serial passages in C57BL/6 mice. On second passage, most of the inoculated mice showed molecular features of the abnormal prion protein (PrP(d)) and brain lesions similar to those observed at first passage, but clearly distinct from those of classical BSE in this mouse model. These features were similarly maintained during a third passage. However, on second passage, some of the mice exhibited distinctly different molecular and lesion characteristics, reminiscent of classical BSE in C57Bl/6 mice. These similarities were confirmed on third passage from such mice, for which the same survival time was also observed as with classical BSE adapted to C57Bl/6 mice. Lymphotropism was rarely detected in mice with H-BSE features. In contrast, PrP(d) was detectable, on third passage, in the spleens of most mice exhibiting classical BSE features, the pattern being indistinguishable from that found in C57Bl/6 mice infected with classical BSE.
CONCLUSION/SIGNIFICANCE: Our data demonstrate the emergence of a prion strain with features similar to classical BSE during serial passages of H-BSE in wild-type mice. Such findings might help to explain the origin of the classical BSE epizootic disease, which could have originated from a putatively sporadic form of BSE.
最近在牛中发现了两种不同形式的非典型海绵状脑病（H-BSE 和 L-BSE）。在几种野生型或转基因小鼠模型中的传播研究表明，这些形式与两种不同的主要传染性病原体株有关，这些病原体株也与在食源性流行疾病期间从经典 BSE 病例中分离出来的独特株不同。
方法/主要发现：在 C57BL/6 小鼠中进行了三次连续传代监测 H-BSE。在第二次传代时，大多数接种的小鼠表现出异常朊病毒蛋白（PrP(d)）的分子特征和与首次传代相似的脑病变，但与该小鼠模型中的经典 BSE 明显不同。这些特征在第三次传代时也得到了同样的维持。然而，在第二次传代时，一些小鼠表现出明显不同的分子和病变特征，类似于 C57Bl/6 小鼠中的经典 BSE。从这些小鼠中进行的第三次传代也证实了这些相似性，对于这些小鼠，也观察到了与适应 C57Bl/6 小鼠的经典 BSE 相同的存活时间。在具有 H-BSE 特征的小鼠中很少检测到淋巴嗜性。相比之下，在第三次传代时，大多数表现出经典 BSE 特征的小鼠的脾脏中可检测到 PrP(d)，其模式与感染经典 BSE 的 C57Bl/6 小鼠中发现的模式无法区分。
结论/意义：我们的数据表明，在野生型小鼠中 H-BSE 的连续传代过程中出现了一种具有类似于经典 BSE 特征的朊病毒株。这些发现可能有助于解释经典 BSE 流行疾病的起源，该疾病可能源自一种假定的散发性 BSE。
