引起免疫失败的IBV分离株的生物学特性及结构基因分析

本研究应用鸡胚尿囊腔接种的方法，从广西患传染性支气管炎的免疫失败的病鸡中分离到一株传染性支气管炎病毒（IBV）（命名GX-YL5），通过间接血凝试验、动物回归试验和气管环交叉中和试验对该毒株进行鉴定和主要生物学特性的研究，同时利用RT-PCR技术扩增克隆该病毒的S1基因和N基因并测定其核苷酸序列。结果表明：该病毒株有间接血凝性；致病性较强；血清型不同于常用疫苗株H120、Ma5、4／91。同源性分析表明，S1基因核苷酸和氨基酸序列与参考株的同源性分别为63.5％-81.2％和50.7％-78.8％；N基因核苷酸和氨基酸序列与参考株的同源性分别为85.7％-87.2％和89.5％-91.7％；S1基因和N基因系统进化分析表明分离株与其它参考毒株的亲缘关系较远。S1基因和N基因分型与血清学试验结果相吻合。本研究结果提示了广西分离株GX-YL5可能是一个新的变异株，这可能是目前免疫失败的重要因素，同时也为研制适合本地使用的IBV疫苗提供了科学依据和物质基础。

Analysis of Biological Characteristics and Structural Genes of IBV Isolate from Chickens with Immunoprophylaxis Defeat

Infectious bronchitis virus(IBV),named GX-YL5,was isolated from flocks with immunoprophylaxis defeat in Guangxi by chick embryo allantoic cavity inoculation. The identification and analysis of important biological characteristics were carried out by indirect hemagglutination test,animal pathogenicity test,chick embryo tracheal organ cultures cross neutralization test. S1 and N gene of GX-YL5 were amplified by RT-PCR technique and the cDNA sequences were determined. The results showed that IBV(GX-YL5),which ...