2006～2008年B型流感病毒泰山分离株血凝素基因序列分析

Analysis of the gene sequence of the HAl region of influenza B viruses isolated in Taian from 2006 to 2008

目的分析泰安市2006~2008年度分离的B型流感病毒HA1基因序列,探究其基因变异特点及种系进化分布,为流感防治提供技术支持。方法采集监测医院流感样病例鼻、咽拭子标本,分离流感病毒并进行型别鉴定,选取部分B型流感病毒株提取病毒RNA,采用逆转录-聚合酶链反应扩增血凝素基因,扩增产物经纯化后进行血凝素基因HAl区核苷酸序列测定并推导编码的氨基酸序列,然后用DNAsTAR MegAlign序列分析软件进行基因种系进化特性分析。结果 2006/2007年度分离的B型流感病毒均为Victroria系;2007/2008年度以Yamagata系为优势株,也有少量Victroria系活动。与B/Shanghai/361/2002/2和B/Tianjin/144/05比较,Yamagata系泰山分离株HA氨基酸替换数为8~10个,所有毒株均在7~9个相同氨基酸位点发生了相同替换;与疫苗推荐株B/Malaysia/2506/2004比较,Vic-troria系泰山分离株氨基酸替换数为2~3个,所有毒株均在HA2个相同氨基酸位点发生了相同替换。结论 Yama-gata系泰山分离株HA1基因特性已发生改变,从基因水平说明当地Yamagata系流行株抗原发生了变异;Victroria系分离株基因特性虽有所改变,但是否已成为有流行病学意义的变异株,尚有待进一步观察。2006/2007年度流感疫苗对当地B型流感应有一定预防作用,2007/2008年度疫苗对B型流感的预防效果欠佳。

Objective To supply technical support in countering the flu,this paper analyzed the DNA sequences of influenza B virus isolated in Taian from 2006 to 2008 to study the characteristics of genetic mutations and phylogenetic distribution of the virus.Methods Specimens of nasopharyngeal swabs were collected from influenza-like cases at surveillance hospitals.Then,viral RNA was extracted and the viral HA gene from viral RNA extracted from certain strains of the virus was amplified by RT-PCR.The PCR products were purified and the nucleotide sequences of HA1 gene were analyzed to deduce the amino acid sequence.Finally,the phylogenetic tree of the virus was depicted using MegAlign software.Results Influenza B virus strains isolated in 2006-2007 were Victoria-like virus,while in 2007 and 2008 a Yamagata-like virus was dominant strain,accompanied by some strains of Victoria-like virus.Compared to B/Shanghai/361/2002 and B/Tianjin/144/05,the number of amino acid replacements was 8-10,and all virus sequences had the same replacement at about 7-9 of the same amino acid sites.Compared to the vaccine strain（B/Malaysia/2506/2004） recommended by the WHO,there were 2-3 amino acids replaced and 2 sites had the same replacement.Conclusion At the genetic level,mutations in antigens in the form of local Yamagata strains were apparent.Despite changes in the genetic characteristics of Taishan Victoria-like isolates,further study should be done to determine if the mutants of epidemiological importance.Influenza vaccine from 2006-2007 should be of some use in preventing local influenza B while that from 2007/2008 may lack effectiveness.