H9N2亚型禽流感病毒广东2009年分离毒株的HA基因功能进化

Phylogenetic analysis of the HA genes of the four H9N2 avian influenza virus isolates from Guangdong Province

采用常规的血清学试验和特异性RT-PCR方法,对A/chicken-Guangdong/E8/2009等4株H9N2亚型禽流感病毒广东分离株的HA基因进行克隆、测序和遗传衍化分析,并与国内疫苗毒株进行比较,力图从分子水平探讨广东H9N2亚型禽流感病毒的演化和变异规律。研究结果显示：4株分离毒株与3株国内疫苗毒株的氨基酸同源性在91.3%-93.3%之间,与09年其他地区分离得到的H9N2亚型禽流感毒株同源性在95.0%-99.2%之间。4株H9N2亚型禽流感病毒比国内所使用的3株疫苗毒株都在第295位新增一个潜在糖基化位点。此外,研究还发现4株分离毒株共有7处氨基酸位点发生突变,其中A316S突变正好位于HA切割位点,而Q216L则位于受体结合位点。本研究从一定程度上反映出2009年国内流行H9N2禽流感优势毒株与国内一些疫苗毒株有一定的进化距离。

HA genes of four H9N2 subtype avian influenza viruses were tested by serological tests and amplified by RT-PCR and then sequenced and analyzed compared with the three domestic vaccine strains.The study aimed to understand the genetic characters of H9N2 subtype avian influenza viruses isolated in Guangdong province.The results of phylogenetic analysis showed that four isolated strains and the three domestic vaccine strains shared the amino acid homology of 91.3%~93.3%,while 95.0%~99.2% sharing with other isolates from other areas in 2009.Comparing with the isolated strains and the vaccine strains,extract PGS was found on 295 sites.The study also showed that 7 amino acid mutations in the isolated strains.Mutation at A316S site was located in HA cleavage site and mutation at Q216L was in receptor binding site.To some extent,the study reflects a certain evolutionary distance between the commercial vaccine strains and prevalent H9N2 subtype avian influenza virus strains.