犬瘟热病毒变异株对水貂致病性增强的分子机制

项目名称： 犬瘟热病毒变异株对水貂致病性增强的分子机制

项目编号： No.31502102

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 水产学、兽医学

项目作者： 赵建军

作者单位： 中国农业科学院特产研究所

项目金额： 20万元

中文摘要： 由犬瘟热病毒（CDV）感染引发的犬瘟热为多种动物共患传染病，CDV血凝素（H）蛋白在介导病毒毒力、受体识别等方面起到重要作用。近年来，犬瘟热在我国毛皮动物养殖地区频繁暴发。我们从犬瘟热病例中分离到CDV-H(I542N,Y549H)基因变异株，动物回归试验证实CDV变异株对水貂呈现更高致病性。542和549位氨基酸位于CDV-H蛋白的SLAM受体结合区（RBS），I542N突变使H蛋白增加了1个潜在N-连接糖基化位点。我们推测I542N和Y549H突变导致了CDV变异株对水貂的高致病性。本项目拟通过氨基酸定点突变、表面等离子共振和反向遗传操作等技术，分别在蛋白表达、细胞感染和动物致病性水平探究CDV-H蛋白542和549位氨基酸突变对病毒蛋白表达、与SLAM受体亲和力及其对水貂致病性的影响，从而阐明CDV变异株对水貂致病性增强的分子机制，为毛皮动物犬瘟热的有效防控提供理论依据。

中文关键词： 犬瘟热病毒；变异株；水貂；致病性；分子机制

英文摘要： Canine distemper virus (CDV), the causative agent of canine distemper, can infect a wide range of hosts. Hemagglutinin (H) protein plays key roles in viral virulence and host cells entry. Recently, CDV variants with 542 and 549 amino acid substitutions (isoleucine to asparagine, tyrosine to histidine) within H protein were identified from naturally infected fur animals in China. These variant isolates showed higher pathogenicity to minks as demonstrated by in vivo inoculation test. The two substitutios occurred within Signaling lymphocyte activation molecule (SLAM) receptor binding sites (RBS), of which the I542N substitution leads to a potentially novel N-glycosylation site. These findings prompt us to hypothesize that 542 and 549 amino acid substitutions may enhance the affinity between CDV-H and mink SLAM receptor. Hence, in order to characterize the relationship of these two substitutes and viral pathogenicity, we employ site-directed mutation, surface pasmon resonance (SPR) and CDV reverse genetic techniques, to determined the influence of H protein on viral proteins expression, receptor affinity and pathogenicity at in vitro and in vivo level, the results will add new inside into the pathogenesis of CDV with respect to the residues within H protein.

英文关键词： Canine distemper virus;Variants;Minks;Pathogenicity;Molecular mechanism