中文摘要：

鸡传染性支气管炎病毒（IBV）在体外进行细胞培养比较困难,并且不同来源毒株在易感性上也存在差异。为揭示IBV适应CK细胞培养的分子基础,优化其细胞培养技术,本研究首先对H120疫苗株和IBYZ分离株的分子克隆株rH120和rIBYZ,在鸡胚、鸡气管环以及原代鸡肾细胞（CK）上培养时组织细胞的嗜性差异进行了比较,结果发现rIBYZ与rH120在CK上的亲嗜性存在显著差异。在此基础之上,课题组借助前期建立的IBV反向遗传操作系统,将H120疫苗株和IBYZ株的S基因进行交叉替换,成功拯救获得2株重组病毒rH120-S/YZ和rIBYZ-S/H120。通过比较不同毒株感染CK细胞后的病变、特异性免疫荧光的强度以及病毒的增殖曲线,表明刺突蛋白（S）在IBV适应CK细胞过程中发挥决定性作用。本文揭示了S蛋白对细胞嗜性的影响,为进一步探索IBV适应细胞的分子机制奠定了基础。

英文摘要：

Avian infectious bronchitis virus（IBV）is difficult to culture in vitro,and there are differences in the susceptibility of different strains.To explore the molecular basis of IBV adaptation to chicken kidney（CK）cell culture and optimize its cell culture technology,differences between the molecular clone strains rH120 and rIBYZ of the H120 vaccine strain and IBYZ isolates in the culture of chicken embryo,chicken tracheal annulus,and CK cells were compared.Results showed a difference in the cytotropism of rIBYZ andrH120 in CK cells.Base on these data,we constructed an IBV reverse-genetic system.We replaced S gene of the vaccine strain H120 and kidney-type virulent strain IBYZ.This strategy led to recue the recombinant strains rH120-S/YZ and rIBYZ-S/H120.We wished to further verify the differences in cell tropism of CK cells.Hence,with respect to their parental strains,we compared the cytopathic effect,fluorescence distribution,and replication of the recombinant virus replaced S gene in CK cells.We found that the S protein was a decisive factor of IBV in cell tropism.Here,we revealed the effect of the S protein on cell tropism.Our data could lay the foundation for further study of the molecular mechanism of cell adaptation to the IBV.