珠海市2007-2008年乙型流感病毒基因特性分析

Characteristic analysis on HA1 gene of influenza virus B,isolated from 2007 to 2008 in Zhuhai

目的了解珠海市近两年乙型流感病毒的基因变异情况。方法采集珠海市流感样病例样本进行流感病毒的分离和鉴定,并对分离到的乙型流感病毒进行核酸的提取,采用逆转录-聚合酶链反应（RT-PCR）扩增病毒基因后进行病毒血凝素HA1基因核苷酸序列测定,用Mega、DNA Star、GeneDoc软件对测序结果进行分析处理,并与WHO推荐的疫苗株基因序列进行比对。结果 2007-2008年分离的乙型流感毒株分属于Yamagata系和Victoria系两个谱系,谱系内毒株间距离很近。Yamagata系毒株与B/Brisbane/3/2007的核苷酸同源性极高,在99.4%~99.7%之间;Victoria系乙型流感病毒株与B/Malasia/2506/2004的核苷酸同源性亦很高,在98.6%~99.1%之间。与疫苗株和其它流行株相比,本次分离的两个谱系毒株均未发现核苷酸的丢失和插入,但均增加一个潜在的糖基化位点。结论珠海市人群交替流行着Yamagata系和Victoria系两个抗原性不同的进化系的乙型流感病毒,病毒的基因发生了变异。2007-2008两年WHO推荐的乙型流感疫苗株与我地区当年流行株为不同谱系毒株,预防保护效果不好。

To understand the variation of hemagglutinin gene HA1 in influenza virus B and evaluate the protective effect of the vaccine strains recommended by WHO,respiratory specimens were collected from the suspected cases in Zhuhai.The influenza viruses were isolated from the specimens and furtherly typed by serological identification.The HA1 genes were sequenced and the data were analyzed by software of Mega,DNA Star and GeneDoc.The results showed that the viruses of Yamagata lineage and Victoria lineage were isolated.The homology of strains in Yamagata lineage and nucleotide acids of B/Brisbane/3/2007 was 99.4%-99.7%.Similarly,the homology of strains in Victoria lineage and nucleotide acids of B/Malasia/2506/2004 was 98.6%-99.1%.Comparing with the vaccine strains and other epidemic strains,there was no deletion or insertion of nucleotide acid in both lineages,but there was a glycosylation site acquired in all the isolated virus strains.It＇s suggested that the two different lineages of Yamagata and Victoria prevailed alternatively in Zhuhai during 2007 to 2008,and the variation of gene was occurred during these years.As the vaccine strains recommended by WHO were different from the epidemic strains in Zhuhai in lineage,the protective effect was unsatisfied.