2015年湖南部分地区H9N2亚型流感病毒HA和NA基因遗传进化

Genetic evolution of HA and NA genes of H9N2 influenza viruses isolated in regions of Hunan Province, China, in 2015

摘要:

我国湖南地区因水禽家禽饲养较多且密集，是流感病毒高发省份。为了监测流感病毒的变异情况，采用RT-PCR技术扩增了10株H9N2亚型流感病毒的HA和NA基因，并进行了序列测定和分析。结果显示，10株分离株均属于欧亚分支中的Y280亚系；HA碱性裂解位点序列均为RSSR↓GLT，为低致病性流感病毒特征；HA受体结合位点234位均为L，具有与人唾液酸α-2,6受体结合的特性；NA蛋白均在颈部 (63–65位) 出现氨基酸缺失，这种缺失能增加流感病毒在哺乳动物中的复制能力。提示H9N2亚型毒株近年有毒力和致病力趋于转强的可能性，因此，要加强对H9N2亚型禽流感病毒的监测，密切关注它的重组趋势。

Abstract:

The high prevalence of influenza A virus is identified in Hunan Province because of the high density of poultry farms. To survey the variations of H9N2 subtype avian influenza virus in Hunan province, we analyzed HA and NA genes of 10 virus strains isolated from different areas of Hunan Province. All these strains belong to the Eurasian lineage, Y280-like sub-lineage. The cleavage sites in their HA genes were all RSSR↓GLT, corresponding to the feature of low pathogenic AIV. All strains had an L (Leu) at the site 234 in the HA genes, indicating the ability of binding with the SAα-2,6 receptor. NA gene stalk deletions at aa 63–65 were also detected from all the isolates, indicating a possibility of increased virus replication in mammals. Our findings suggest that more attention should be paid to the surveillance of H9N2 influenza virus and its direction of reassortment.