2016年北京市房山区B型Victoria系流感病毒基因特性分析

Analysis on gene characteristics of influenza B Victoria lineage viruses in Fangshan District of Beijing in 2016

目的了解北京市房山区2016年B型Victoria系流感病毒HA1基因变异情况。方法随机选择2016年流感病原学监测中分离到的B型Victoria系毒株共13株,采用反转录PCR(RT-PCR)法扩增病毒目的基因片段后进行序列测定,与WHO推荐的疫苗株进行比对并构建进化树。采用MEGA6软件对测序结果进行分析,同源性计算使用BLAST网站。结果 2016年房山区B型Victoria系流感病毒HA1目的基因片段序列测定拼接后最长核苷酸片段为1 081 bp,编码氨基酸为360个,与2015—2016年的疫苗株B/Brisbane/60/2008比较,13株流行株的氨基酸在第132、144位点有变异,其他位点的氨基酸变异呈散在性;与2008—2009年的疫苗株B/Florida/4/2006比较,13株流行株的氨基酸部分位点的变异具有普遍性。做进化树分析,房山区2016年分离到的B型Victoria系流感病毒与疫苗株B/Brisbane/60/2008在同一个分支上,距离较近。结论 2016年北京市房山区B型Victoria系流感病毒HA1基因在抗原决定簇区有一定的变异,但疫苗株B/Brisbane/60/2008有保护作用,应继续关注氨基酸的替换。

[Objective]To analyze the genetic characteristics of HA1 fragment of influenza B Victoria lineage viruses in Fangshan District of Beijing in 2016.[Methods]A total of 13 strains belong to B Victoria Lineage Viruses were selected randomly,and these strains had been isolated in influenza etiology surveillance in 2016. HA1 gene of B influenza Victoria Lineage virus was amplified with reverse transcription-polymerase chain reaction（RT-PCR）and sequenced for gene evolution characteristics analysis with vaccine strains recommended by WHO. MEGA6 software was used to analyze the sequencing results and BLAST website was used to calculate the homology.[Results]The length of the nucleotide sequence of HA gene obtained by sequencing was 1 081 bp,encoding 360 amino acids（aa）. Compared with the vaccine strain B/Brisbane/60/2008 in 2015-2016,the amino acids of the 13 strains belong to B Victoria Lineage Viruses were different at the 132 and 144 sites,with sporadic variation of amino acid in other sites. Compared with the vaccine strain B/Florida/4/2006 in 2008-2009,the variations of amino acid in some sites were universal. The phylogenetic tree analysis showed that influenza B Victoria Lineage Viruses in Fangshan District of Beijing in 2016 was close to the vaccine strain B/Brisbane/60/2008 and they were on the same branch.[Conclusion] HA1 gene of Victoria influenza B virus in Fangshan District of Beijing has been mutated in the region of antigenic determinant in 2016,but the vaccine strain B/Brisbane/60/2008 has a protective effect. It is necessary to continue to pay attention to amino acid replacement.