2014-2016年福建省H3N2亚型流感病毒血凝素基因特征分析

Characteristics of influenza A (H3N2)virus hemagglutinin genes in Fujian province from 2014 to 2016

目的了解2014—2016年福建省H3N2亚型流感病毒血凝素(HA)基因特征及其变异情况。方法随机选取44株病毒,对病毒的HA基因进行扩增和测序;然后利用生物信息学软件和在线分析网站对序列进行拼接、校对、相似性与差异性比较以及基因进化树构建等基因特征分析。结果44株H3N2亚型流感病毒HA基因核苷酸相似性在97.3%-100.0%之间,2014年、2015年与2016年流行株与对应疫苗株之间的平均基因差异分别为0.012、0.008和0.009。2014年流行株的基因型为3C.3a,与疫苗株3C.1不同,2015年与2016年流行株与疫苗株的基因型相同,但其抗原表位、受体结合位点和糖基化位点发生了变异。结论2014-2016年福建省H3N2亚型流感病毒逐年发生变异,显示出逃避疫苗免疫作用的能力,应加强流感监测,以及时发现变异情况,为流感防控提供科学依据。

Objective To investigate the genetic characteristics and mutations in hemagglutinin (HA)genes of influenza A subtype H3N2viruses isolated in Fujian province during 2014--2016.Methods HA gene fragments of 44randomly selected influenza A (H3N2)viruses were amplified by RT-PCR and then sequenced by Sanger sequencing.Obtained sequences were analyzed by bioinformatics software and on- line websites.Results Pair-wise similarity among HA genes of the 44strains was between 97.3%-100.0% at nucleotide level.The average variations between epidemic strains and corresponding vaccine strains in the year of 2014,2015and 2016were 0.012,0.008and 0.009,respectively.The genotype of epidemic strains in 2014was 3C.3a rather than 3C.1 of the vaccine strain.Notably,variations at some antigenic sites,re- ceptor binding sites (RBSs)and N-Glycosylation sites were identified despite the fact that the genotypes were identical between epidemic and vaccine strains in 2015and 2016.Conclusion Variations at the HA genes of influenza A (H3N2)viruses in Fujian province occurred during the year of 2014--2016,reflecting the ability of circulating strains to escape the vaccine-induced immunity.Sustainable influenza surveillance and prompt identification of viral variants would benefit influenza prevention and control.