IMMUNOBIOLOGY OF SCRAPIE VIRUS INFECTION

羊瘙痒病是一种自然发生的羊海绵状脑病， 山羊引起的临床和病理变化类似于 克雅二氏病和库鲁病。传染源是 对大多数病毒和疾病的病原体有显著的抵抗力 导致检测不到宿主免疫应答。 的亲密关系 羊瘙痒病与宿主蛋白质可能解释了它的许多不寻常的特征。 在 为了获得不含组织污染物的制剂，我们试图 建立高滴度羊瘙痒病感染的组织培养细胞系。 神经母细胞瘤细胞系成功地感染了羊瘙痒症因子， 通过二维凝胶电泳分析羊瘙痒症特异性 蛋白质和“朊病毒”蛋白的存在。 没有蛋白质是 鉴定未感染或感染的培养物。 试图 代谢标记羊瘙痒病相关核酸也 不成功。 尽管该细胞系保持了显著的感染性， 可能太小而不允许检测某些Sc相关功能。 因此，将尝试从受感染的细胞中克隆受感染的细胞。 培养物从而富集Sc相关功能。 为了研究朊蛋白与羊瘙痒病的关系， 使用PCR方法分离羊瘙痒症朊病毒蛋白（PrP 27 -30）的cDNA克隆， 基于一部分的预测的mRNA序列的寡核苷酸探针， 这种蛋白质。 该克隆的部分DNA序列表明， 与预测的PrP 27 -30 mRNA相同。 该克隆的杂交 在感染和未感染羊瘙痒症的组织中均检测到一条2.4- 2.5kb的mRNA带 小鼠和仓鼠脑，但在脾或肝中没有。 因此，PrP 27 -30 mRNA 不是羊瘙痒症特有的，而是一个正常的大脑编码， 蛋白 类似的方法将用于搜索羊瘙痒症特异性 标记。

Scrapie is a naturally occurring spongiform encephalopathy of sheep and goats which causes clinical and pathological changes similar to those of Creutzfeldt-Jakob and Kuru diseases of man. The infectious agent is markedly resistant to agents that inactivate most viruses and disease results in no detectable host immune response. The intimate association of scrapie with host protein may account for many of its unusual features. In order to obtain agent free of tissue contaminants, we have sought to establish high titered scrapie infected tissue culture cell lines. Neuroblastoma cell lines were successfully infected with scrapie agent and analyzed by two-dimensional gel electrophoresis for scrapie-specific proteins and for the presence of the "prion" protein. No protein unique to either the uninfected or infected culture was identified. Attempts to metabolically label scrapie associated nucleic acids were also unsuccessful. Although the cell line maintains significant infectivity, it may be too little to allow detection of certain Sc related functions. Therefore, an attempt will be made to clone infected cells from the cultures thus enriching for Sc related functions. In order to study the relation of the prion protein to scrapie disease a cDNA clone of the scrapie prion protein (PrP27-30) was isolated using an oligonucleotide probe based on the predicted mRNA sequence of a portion of this protein. The partial DNA sequence of this clone indicated that it was identical to the predicted PrP27-30 mRNA. Hybridization of this clone detected a 2.4-2.5 kb mRNA band in both scrapie-infected and uninfected mouse and hamster brain, but not in spleen or liver. Thus, PrP27-30 mRNA was not scrapie-specific, but instead appeared to encode a normal brain protein. Similar approaches will be used to search for scrapie specific markers.