2004～2006年江西省乙型流感病毒HA1基因特性分析

Analysis on genetic characterizations on HA1 region of influenza B viruses isolated in Jiangxi Province from 2005 to 2006

目的：了解江西省2004～2006年分离的B型流感病毒株HA1基因变异特征。方法：采集监测医院和疑似流感疫情的流感样病例鼻咽拭子标本进行流感病毒分离,对分离到的B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核苷酸序列测定,用DNAStar5.0、BioEdit（Version5.0）、Mage生物软件对测序结果进行分析处理,推导出氨基酸序列,进行基因特性分析。结果：2004年和2005年分离到的B型流感病毒均为B型的Yamagata系;2006年以Victoria系为优势株,但有Yamagata系的活动。9株Yamagata系B型流感病毒HA1区域核苷酸序列长度均为1014 bp,未发现核苷酸的丢失和插入,与疫苗推荐株B/Shanghai/361/2002 HA1区相比较,不同毒株氨基酸同源性为96.4%～97.3%,替换数在10～11个,所有毒株均在9个相同的氨基酸位点发生了相同的替换,在196位增加了一个糖基化位点。12株Victoria系B型流感病毒HA1区域核苷酸序列长度均为1017 bp,未发现核苷酸的丢失和插入,与疫苗推荐株B/Malaysia/2506/2004的HA1区相比较,不同毒株氨基酸同源性为98.4%～99.5%,替换数在2～4个,所有毒株均在2个相同的氨基酸位点发生了相同的替换,在197位增加了一个糖基化位点。结论：江西省2004～2006年Yamagata系B型流感病毒HA1基因特性已发生改变,从基因水平说明Yamagata系B型流感病毒抗原性发生了改变。2006年Victoria系B型流感病毒HA1基因特性有所改变,疫苗仍有预防效果。

Objective：To understand the genetic variation characterizations of influenza B viruses isolated in Jiangxi Province from 2005 to 2006.Methods：The specimens of nasopharyngeal swabs were collected from influenza like cases of monitor hospitals and influenza epidemic situation.RNA was extracted from the influenza B viruses isolated from the specimens,then their HA1 genes were amplified by reverse transcription polymerase chain reaction（RT-PCR）.The PCR products were sequenced and the data obtained were analyzed with the software DNAStar5.0,BioEdit（Version5.0） and Mage.The amino acid sequences were deduced,then gene conversion levels were assessed.Results：The influenza B viruses isolated from 2004 to 2005 were Yamagata-like viruses.The Yamagata-like and Victoria-like viruses co-circulated in 2006.But the Victoria-like virus was prevailing strain.The nucleotides of HA1 region of 9 strains come from Yamagata-like viruses were all 1014 bp,there were no deletion and insertion in the nucleotides.Compared with vaccine strain（B/Shanghai/361/2002） recommended by WHO at that time,there were 96.4%~97.3% identity in amino acid sequence,10~11 amino acids changed.And all virus sequences had 9 amino acids changed on the same sites.There was one more N-glycosylation located at 196th site.The nucleotides of HA1 region of 12 strains come from Victoria-like viruses in 2006 were all 1017 bp,there were no deletion and insertion in the nucleotides.Compared with vaccine strain（B/Malaysia/2506/2004） recommended by WHO at that time,there were 98.4%~99.5% identity in amino acid sequence and 2~14 amino acids changed,and all virus sequences had 2 amino acids changed on the same sites.There was one more N-glycosylation located at 197th site.Conclusion：The genetic characterizations on HA1 regions of Yamagata-like viruses isolated from 2004 to 2006 in Jiangxi had changed.In genetic level,the hemagglutinin antigenicity had changed.The Victoria-like virus isolated in 2006 had changed a little,but the vaccine produced by the influenza B vaccine strain recommended by WHO in 2006 had protective effect.