STUDY ON THE NERVE-IMMUNE SYSTEMS AND CELLULAR FACTORS INFLUENCE TO THE PATHOGENICTTY AND DISTRIBUTION OF PRP^<Sc>IN ANIMAL PRION DISEASES

动物朊病毒病的发病机制受朊病毒毒株、遗传因素、自然免疫和宿主细胞因子的影响。本研究主要从遗传因素、神经免疫系统和巨噬细胞摄取PrP^3<Sc>三个方面进行了研究。得到以下结果. PrP基因的多态性：对日本863头黄牛、118头山羊和136头西卡鹿PrP基因的多态性进行了检测。在黄牛和西卡羊中发现了多个单核苷酸多态性（SNPs），但未发现氨基酸替换。在118个山羊品种中发现了2个与羊瘙痒病抗性相关的多态性位点.牛和羊的神经系统：为了确定支配牛和羊回肠的交感神经元、副交感神经元和感觉神经元的位置、数目和节段性分布，进行了辣根过氧化物酶示踪实验。标记神经元在牛和羊的腹腔和肠系膜前神经节复合体中被检测到。仅在肠系膜尾神经节和椎旁神经节内存在少量标记神经元.免疫细胞摄取PrP1<Sc>：为了阐明免疫细胞摄取PrP1<Sc>，研究了朊病毒感染早期阶段牛巨噬细胞的参与。羊瘙痒病脑匀浆和疯牛病脑匀浆在牛巨噬细胞和牛外周免疫细胞中依次降解，部分研究结果已发表在论文中，其余部分正在论文中准备。

The pathogenesis of animal prion diseases is influenced by prion strain, genetic factors, natural immunology and several cellular factors in the affected hosts. In this study, genetic factors, nerve-immune system and uptake of PrP^<Sc> by macrophages were mainly studied. The following results were obtained.1. Polymorpbisms of PrP gene: Polymorphisms of the 863 cattle, 118 caprine and 136 sika dear (Cervus Nippon) PrP genes in Japan were examined. Several single-nucleotide polymorphisms (SNPs) were found in cattle and sika dear, but not find any amino acid substitutions. Two polymorphisms associated with the resistance to scrapie were found in 118 caprine.2. Bovine and sheep nerve systems: To determine the location, namber and segmental distribution of sympathetic, parasympathetic and sensory neurons innervating the ileum in cattle and sheep, tracer experiments with horseradish peroxidase were conducted. The labeled neurons were detected in the celiac and cranial mesenteric ganglion complex in both cattle and sheep. Only a few labeled neurons existed in the caudal mesenteric ganglion and the paravertebral ganglia.3. Uptake PrP^<Sc> by immune cells: To clarify the uptake the PrP^<Sc> by immune cells, the involvement of bovine macrophage in the early stage of prion infection was studied. Brain homogenates of scrapie and BSE were degraded sequentially in bovine macrophage and bovine peripheral immune cells.A part of this research has been published in the papers, the other parts are now prepared in the papers.