2012-2023年淄博市H3N2亚型流感病毒血凝素基因特征分析

Genetic Characterization of the Hemagglutinin Gene of the Influenza A(H3N2)Virus in Zibo City,China,from 2012 to 2023

了解2012-2023年10个流感监测年度淄博市分离的流感病毒H3N2亚型血凝素(Hemagglutintin,HA)基因及氨基酸变异特征,为流感的防控提供理论依据。对淄博市2012-2023年分离到的39株H3N2流感毒株HA基因进行测序,利用生物信息软件对测序结果进行进化分析和抗原变异分析。2012-2023年淄博市测序H3N2亚型流感分离株A、B、C、E等四个抗原区均有氨基酸发生变异,D区相对保守,未检测到变异;2012-2016年部分毒株受体结合位点左壁发生N225D变异,2016-2023年所有毒株左壁均发生N225D突变,2016-2023年部分毒株前壁发生T131K变异,2019-2020年部分毒株前壁发生T135K、S137F变异,其余位点未发生变异;与WHO推荐的相应年度参考疫苗株相比,各年度的分离株均出现了糖基化位点增加或缺失现象,且多发生于A区抗原位点和受体结合位点前壁;全部分离株均位于3C分支,大部分年度流感流行株分支较为集中,但也存在某年度多分支流行情况;与参考疫苗株比较,2015-2016年度、2019-2020年度分离株与当年推荐疫苗株遗传距离较远。2012-2023年淄博市H3N2亚型流感病毒HA基因表现出遗传多态性,在基因进化上呈现多分支进化特点,部分年度与当年WHO推荐疫苗株在基因水平上有一定遗传距离,提示抗原匹配程度可能降低,应密切关注流感病毒基因变异情况,为流感疫情防控和疫苗的筛选提供科学依据。

To characterize the hemagglutinin(HA)gene of the influenza A(H3N2)virus from 2012 to 2023 in Zibo City,China,to provide a scientific basis for the prevention and control of influenza epidemics.Thirty-nine strains of the HA gene of the influenza A(H3N2)virus isolated in Zibo City,China from 2012 to 2023 were sequenced.Bioinformatics software was used to analyze evolution and antigen variations.From 2012 to 2023,amino-acid variations occurred in four regions(A,B,C,E)in isolates of the influenza A(H3N2)virus sequenced in Zibo City,China.The D region was relatively conserved,and variation was not detected.From 2012 to 2016,some strains experienced N225D mutations in the left wall of receptor-binding sites.From 2016to 2023,all strains experienced N225D mutations in the left wall.From 2016 to 2023,some strains experienced T131K mutations in the front wall.From 2019 to 2020,some strains experienced T135K and S137F mutations in the front wall,whereas the remaining sites did not undergo mutations.Compared with the corresponding annual reference vaccine strains recommended by World Health Organization(WHO),the isolated strains in each year showed an increase or loss of glycosylation sites,which occurred mostly in the front wall of A-region antigen sites and receptor-binding sites.All isolated strains were located in the 3C branch,and most of the annual influenza epidemic strains had concentrated branches,but there were also cases of multi-branch outbreaks in a certain year.Compared with the reference vaccine strain,the genetic distance between the isolated strains from 2015–2016 and 2019–2020 was far from the recommended vaccine strain for that year.From 2012 to 2023,the HA gene of the influenza A(H3N2)virus in Zibo City showed polymorphism and multi-branch evolutionary characteristics.In some years,there was a certain genetic distance between our strain and WHOrecommended vaccine strains,indicating that the degree of antigen matching may decrease.Close attention should be paid to the genetic variation of influenza viruses to provide scientific basis for the prevention and control of influenza epidemics and vaccine screening.