IMMUNOBIOLOGY OF SCRAPIE VIRUS INFECTION

痒病是一种海绵状脑病，在自然条件下， 影响绵羊和山羊。 类似的疾病在水貂身上也有描述， 黑尾鹿麋鹿最近还有牛 牛的疾病 在英国的奶牛群中达到了流行病的程度。 至少 三种人类疾病，克雅氏病、库鲁病和格斯特曼病， 斯特劳斯勒综合征，在组织学上与羊瘙痒症难以区分。 现有证据表明，所有这些疾病都是由 类似的传染源。 导致这些的传染性病原体 疾病是特别有趣的，因为没有核酸基因组 与他们有联系。 含有大量 羊瘙痒病感染性确实含有聚集的蛋白酶K（PK）抗性 一种内源性蛋白质，命名为PrP。 PK抗性形式的 这种蛋白质（PrP-res）对海绵状血管疾病具有特异性， 脑病组。 此外，一些实验证据表明， PrP-res在疾病发病机制中的重要性。 然而， 争议围绕PrP-res和 羊瘙痒病的传染媒介。 一些研究人员认为PrP-res本身 羊瘙痒病的病原体 或者，这种蛋白质可能是 或者仅仅作为疾病的副产品积累。 不管这种关系如何，PrP-res的检测提供了一个重要的 研究海绵状脑病的工具。 我们利用羊瘙痒病感染的细胞培养， 羊瘙痒病病原体和PrP PrP以两种形式存在，Prp-sen被发现 仅在羊瘙痒病感染的动物中，并且容易因暴露于PK而被破坏， 和PrP-res，其仅在羊瘙痒病感染的动物中发现， 部分抵抗PK破坏。 我们已经证明， 免疫印迹法检测PrP-res与 瘙痒病病原体的存在 由于最近爆发的牛 海绵状脑病和潜在的风险，受感染的牛可能 对于人类，我们已经开始了研究，这可能会导致更快的 诊断海绵状脑病的方法。 其他研究涉及 PrP基因对羊瘙痒病潜伏期的影响， 易感性，可能解释物种向性的机制和研究 寻求确定导致PrP-sen转换为 我们也在努力寻找更好的方法来灭活 高滴度羊瘙痒病感染的组织和表面。

Scrapie is a spongiform encephalopathy which under natural conditions affects sheep and goats. Similar diseases have been described in mink, mule deer, elk, and most recently, cattle. The disease in cattle has reached epidemic proportions within Great Britain's dairy herds. At least three human diseases, Creutzfeldt-Jakob disease, Kuru, and Gerstmann- Straussler syndrome, are histologically indistinguishable from scrapie. Available evidence suggests that all of these diseases are caused by similar transmissible agents. The infectious agents which cause these diseases are particularly interesting because no nucleic acid genome has been associated with them. Preparations that contain large amounts of scrapie infectivity do contain an aggregated proteinase K (PK)-resistant form of an endogenous protein, designated PrP. The PK-resistant form of this proteins (PrP-res) is specific for diseases of the spongiform encephalopathy group. Furthermore, some experimental evidence suggests that PrP-res is important in disease pathogenesis. However, considerable controversy surrounds the exact relationship between PrP-res and the infectious agent of scrapie. A few investigators believe PrP-res is itself the scrapie agent. Alternatively, it's possible that the protein could be a component of the agent or merely accumulate as a byproduct of disease. Regardless of the relationship, detection of PrP-res offers an important tool for the study of the spongiform encephalopathies. We have utilized scrapie-infected cell cultures which we developed to study the scrapie agent and PrP. PrP exists in two forms, Prp-sen which is found only in scrapie-affected animals and is easily destroyed by exposure to PK, and PrP-res which is found only in scrapie-affected animals and is partially resistant to destruction by PK. We have shown that a close association exists between the detection of PrP-res by immunoblotting and the presence of the scrapie agent. Due to the recent outbreak of bovine spongiform encephalopathy and the potential risk that infected cattle might have for humans, we have initiated studies which could lead to a more rapid method for diagnosing spongiform encephalopathies. Other studies deal with the influence of the PrP gene on scrapie incubation period and susceptibility, mechanisms that might explain species tropism and studies seeking to determine factors which account for the conversion of PrP-sen to PrP-res. We are also trying to identify better methods for inactivating high titered scrapie-infected tissues and surfaces.