传染性支气管炎病毒非结构蛋白15分子特性及免疫原性研究

Infectious Bronchitis Virus (IBV) as a RNA virus, is easy to get genetic diversity, resulting the caused infectious bronchitis (IB) as one of the most difficult controlled contagious viral disease, which is responsible for huge economic losses in the poultry industry. So far, few studies on IBV nonstructural protein has been paid attention. In this study, we are focus on nonstructral protein 15 (nsp15) of IBV to study the difference of nsp15 sequences among different tissue tropism viruses, different genotype viruses, and different passaged viruses; the gene and protein expression pattern of nsp15 among different tissue tropism IBVs; and the conservatism and variability of nsp15 epitopes; as well as the immunogenicity of nsp15s between different tissue tropism strains and vaccine strains. The purpose of this study is to clarify the molecular characteristics of IBV nsp15 and evaluate its function as a biological marker for distinguish the infection between field strains and vaccine strains,and provide an good fundation for development of novel differential detection for IBV infection.

传染性支气管炎病毒（IBV）作为RNA病毒，以容易发生突变为特征，其诱发的传染性支气管炎是当今家禽养殖业危害最严重、控制难度最大的病毒性传染病之一。IBV非结构蛋白的研究一直以来很少关注。本项目以IBV非结构蛋白15（nsp15）为靶标，研究不同组织嗜性、基因型及不同鸡胚传代次数毒株的nsp15基因序列差异性；研究不同IBV毒株感染宿主细胞后nsp15在基因和蛋白水平上的表达差异；研究不同组织嗜性IBV nsp15的B细胞抗原表位保守性与变异性；以及研究不同组织嗜性IBV野毒株与疫苗毒株nsp15的免疫原性，阐明IBV nsp15的分子特性及其作为鉴别疫苗毒与野毒鉴别生物标记的可行性，为研究IBV的鉴别检测方法提供理论依据。

传染性支气管炎病毒（IBV）是严重危害养禽业健康发展的重要病毒。IBV的非结构蛋白研究一直以来很少被关注。本研究开展了IBV nsp15分子特性及其抗原性研究。基于IBV nsp15遗传进化分析显示，呼吸型和肾型IBV毒株分别归于两个分支，说明了不同组织嗜性IBV毒株nsp15氨基酸序列间存在差异，不同基因型毒株免疫动物血清中nsp15抗体水平与S1的抗体水平相比也存在明显差异；制备的IBV nsp15的单克隆抗体可与不同IBV基因型毒株反应，并在此基础上鉴定了IBV nsp15的两个抗原表位；IBV nsp15酶活性位点的突变导致酶活性丧失，但可以提高蛋白的表达水平和保持蛋白的抗原性；发现IBV nsp15功能域I和III在细胞中以点状分布，而功能域II则弥散地分布在细胞浆中。功能域II可抑制功能域I在细胞中的点状分布，却不能抑制功能域III的点状分布形式。本研究为今后深入研究和应用IBV非结构蛋白的功能奠定了基础。