嗜肾型鸡传染性支气管炎W93株活疫苗的研究及其S1基因的克隆与序列测定

利用鸡胚分离法由发生肾病变型传染性支气管炎 (IB)的病鸡分离到嗜肾型传染性支气管炎病毒 (NIBV)W株 ;再通过SPF鸡胚连续传代 ,获得了NIBV疫苗毒株W93;继而借助RT PCR法扩增了其S1基因 ,并测定了S1基因的核苷酸序列 ,分析了与相关毒株间的同源性。结果显示 ,W93株在鸡胚中的病毒产量达 10 7.8EID50 /0 .1mL ,适用于所有日龄的雏鸡 ;W93S1基因的核苷酸序列与马萨诸塞型的M4 1株、H52 株和H12 0 株的同源性很高 ,分别为 96 .9%、96 .8%和 97.1%。表明 ,W93可作为制备IB弱毒疫苗的毒株

Isolation and attenuation of nephropathogenic avian infectious bronchitis virus W93 strain and sequencing of the S1 gene

A virulent nephropathogenic avian infectious bronchitis virus(NIBV)strain tentatively named as W strain was isolated from chickens infected with NIBV by the avian embryo isolation method in China. The strain was identificated systematically through chicken and embryo infection tests,pathogen identification , virus interaction test, morphology test, serological identification and virulence assay. The strain was passaged from generation to generation in chicken embryo. After being carried out security and immunology tests a low virulent strain designated as W 93 was abtained. The EID 50 of the embryo fluid infected with W 93 strain was 10 7.8 /0.1 mL. The W 93 strain possessed well security and immunogenicity for all age of chickens. One pair of primers for being amplified S1 gene of avian infectious bronchitis virus (IBV) had been designed, with which the predicted 1.62kb fragment had been amplified via RT PCR from nephropathogenic strain W 93 . The fragment was sequenced and compared with S1 gene of standard strains such as H52, M41, H120 and BEAU. The results showed that the homologies of nucleic acids between W 93 strain and H52, M41, H120 and BEAU strains were 96.8%, 97.1%, 96.9% and 96.8% respectively . The high homology of S1 gene of nephropathogenic strain W 93 with those of other IBV reference strains had been proved.