IMMUNOBIOLOGY OF SCRAPIE VIRUS INFECTION

羊痒病是一种自然发生的绵羊海绵状脑病。 与引起临床和病理变化相似的山羊 人类的克雅氏病和库鲁病。独一无二的 被称为普里恩蛋白(PrP)的蛋白质是一种主要的 含有瘙痒病传染性和致病性的纯化样品的成分 被一些人认为是感染源。这只是 尽管如此，蛋白质还是以次要物质的形式通过- 体内疾病的产物。要区分这两个 我们研究了PrP在皮肤瘙痒病体外生物合成的可能性 脉冲追踪法检测感染和未感染的神经母细胞瘤细胞 标签实验。PrP的生物合成没有差异 发现，这表明PrP在瘙痒病中起次要作用 发病机制。 因为动物组织没有提供令人满意的底物 对于瘙痒病病原体的生化分析或分离，我们 已经继续发展和改进了一种体外感染的瘙痒病 我们之前所描述的细胞培养系统。瘙痒病感染 培养物来源于单个阳性细胞，含有50- 比未克隆的培养物中发现的制剂多100倍。通过 扩增培养中几乎每个细胞的频率分析都在继续 用来控制瘙痒病试剂。细胞剂量-感染性关系是 研究并开发了一种标准曲线，该曲线允许不同的 要比较的文化，因此显著减少了 滴定各种样品所需的动物的数量。这些文化将 用于试剂提纯方法的测试。

Scrapie is a naturally occurring spongiform encephalopathy of sheep and goats which causes clinical and pathological changes similar to those of Creutzfeld-Jakob and Kuru diseases of man. A unique protein called prion protein (PrP) has been found to be a major component of purified samples containing scrapie infectivity and is believed by some people to be the infectious agent. It is just as possible though that the protein accumulates as a secondary by- product of the disease in vivo. To discriminate between these possibilities we studied PrP biosynthesis in vitro in scrapie infected and uninfected neuroblastoma cells using pulse-chase labelling experiments. No differences in PrP biosynthesis were found, and this suggested a secondary role for PrP in scrapie pathogenesis. Because animal tissues have not provided satisfactory substrates for the biochemical analysis or isolation of the scrapie agent, we have continued to develop and improve an in vitro scrapie infected cell culture system which we described before. Scrapie infected cultures were derived from single positive cells and contained 50- 100 fold more agent than was found in uncloned cultures. By frequency analysis nearly every cell in expanded cultures continued to contain scrapie agent. Cell dose-infectivity relationships were studied and a standard curve was developed which allowed various cultures to be compared, thus significantly reducing the numbers of animals needed to titrate various samples. These cultures will be used to test methods for agent purification.