【摘要】 为了解传染性支气管炎病毒(IBV)H120疫苗病毒株的变异情况,本研究利用设计的16对引物扩增分离株ck/CH/LHLJ/090908的基因组序列,并采用3’-RACE和5’-RACE技术,扩增得到该病毒全基因组序列。通过与已发表参考病毒株的全基因组序列进行比较分析,结果表明该分离株基因组全长为27 609 nt,其基因排序未发生改变,纤突蛋白裂解位点为533RRFRR537。遗传进化分析表明该分离株与H120疫苗株的基因组具有高度同源性(99.7%),进化亲缘关系最近。对其基因组序列进行进一步的分析表明,该分离株的E基因发生了248 nt~280 nt连续33个核苷酸的缺失,导致其编码的E蛋白缺失11个氨基酸,推测该分离株为H120疫苗株在鸡群中自然传代进化的变异株。更多还原

【Abstract】 To investigate the mutations of avian infectious bronchitis virus(IBV) vaccine strain of H120, the complete genome of IBV ck/CH/LHLJ/090908, isolated from H120 vaccinated commercial chicken flocks, was amplified by RT-PCR and sequenced including 3’- and 5’-terminals with 16 pairs of primers. The sequences analysis showed that the 27,609 nt of ck/CH/LHLJ/090908 had the typical cleavage site of533RRFRR537 in spike protein, but no change in the gene order. In addition, the isolate shared 99.7%similarity of complete genomic sequence with H120 vaccine strain. However, a 33 nt consistent deletion was found in ORF3 c from248 nt to 280 nt resulting in consecutive deletions of 11 amino acids in E protein of the isolate. Therefore, we speculated that ck/CH/LHLJ/090908 isolate might evolve or mutate from the H120 vaccine strain when passed successively in chicken flocks.更多还原