2005-2009年大连市流感病毒血凝素基因遗传特性分析

Genetic characterization of HA gene of influenza virus isolated in Dalian city during 2005-2009

目的分析大连市2005-2009年流感病毒血凝素(HA)基因变异情况。方法采用MDCK细胞分离培养季节流感H1N1亚型28株;H3N2亚型9株;B型(Yamagata系)24株,采用RT-PCR法分节段扩增各毒株血凝素基因,并进一步对各片段进行核苷酸和氨基酸序列测定分析。结果 2005-2009年,大连市分离到的甲型H1N1病毒变异较大,其中2009年分离的一株H1N1亚型毒株A/liaoningxigang/136/2009(H1)与该年WHO推荐的疫苗株相比,抗原决定簇B区上有4个位点发生了突变,属于新的变种。2005、2007年分离的H3N2流感病毒株,与疫苗株相比序列同源性较高,并未发生大的变异;2007-2008年流行的B型Yamagata系病毒与疫苗株B/Shanghai/361/02相比,有7个氨基酸位点发生改变,其中两个位于抗原决定簇,并于196位增加一个糖基化位点。结论各年度WHO推荐的疫苗株与流行株之间匹配性不完全一致,每年由于核苷酸序列的变化而引起了不同程度的抗原性漂移。

Objective To study genetic mutations of the hemagglutinin gene and molecular epidemiology of influenza in Dalian city during 2005-2009.Methods 28 H1N1,9 H3N2 and 24 influenza B（Yamagata lineage） strains were isolated from MDCK cells.The HA cDNA fragments of them were amplified by RT-PCR,and gene sequences were analyzed on homology and heredity evolution.Results There was a high rate of mutations in H1N1 virus strains isolated from Dalian during 2005-2009.Compared with vaccine strains recommended by WHO,an H1N1 subtype A/liaoningxigang/136/2009（H1） isolated in 2009 had 4 sites mutations on epitope B,which belonged to new variants.H3N2 isolated in 2005 and 2007 showed little degree of variation compared with vaccine strains.Compared with vaccine B / Shanghai / 361/02,Influenza B（Yamagata lineage） isolated during 2007-2008 had 7 amino acids changed sites,two of which were located in the epitope and one new glycosylation on site 196.Conclusion Vaccine strains recommended by WHO and the epidemic strains are not totally consistent.Variable degrees of antigenic drift are caused by annual changes of nucleotide sequences.