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目的了解珠海市2008-2009年乙型流感病毒HA1基因变异情况。方法按照采样时间,选取珠海市2008-2009年每月用狗肾传代细胞(MDCK)培养分离到的第1、2株乙型流感毒株共25株,没分离到毒株的月份不选,提取病毒RNA,RT-PCR扩增HA1基因片段,产物纯化测序,推导氨基酸序列,进行基因进化特性分析。结果 2008年珠海市乙型流感毒株在8月达到分离高峰,晚于A型流感毒株分离高峰时间7月,2009年其在4月达分离高峰,早于A型流感毒株分离高峰时间5月。2008-2009年珠海市流行的乙型流感病毒优势株为Victoria系病毒。与北半球国际疫苗株B/Florida/4/2006 like-virus(GenBank序列号CY033876.1)相比,2008-2009年珠海市流行的Yamagata系乙型流感病毒HA1片段有7个氨基酸位点发生替换:分别是103 K→R,212D→N,其中08-1267、09-0233和09-0240毒株的218N→S,08-190毒株的123P→A、245S→G、270P→S,除08-190外另5株毒株的181N→Y、245S→D,氨基酸同源性高于97%。其中有2个参与构成抗原决定簇的氨基酸位点发生替换,没有发生病毒抗原漂移。Victoria系毒株与疫苗代表株的同源性低于89%。结论 2008-2009年珠海市流行的Yamagata系乙型流感病毒与疫苗代表株同源性极高,本年度的流感疫苗株对珠海市乙型流感病毒流行的防治起了一定作用。2008-2009年珠海市流行的乙型流感病毒优势株属Victoria系,故本年度的流感疫苗株不能对珠海地区流行的乙型流感提供最佳保护。珠海市2008年乙型流感病毒流行时间较长,2009年流行高峰提前可能与此有关。
Objective To understand the mutation of HA1 gene of influenza B virus in Zhuhai from 2008 to 2009. Methods According to the sampling time, a total of 25 strains of first and second influenza B strains isolated from Zhuhai city in 2008-8 were isolated from MDCK. The viral RNA was extracted, the HA1 gene fragment was amplified by RT-PCR, the product was purified and sequenced, and the amino acid sequence was deduced to analyze the gene evolution characteristics. Results In 2008, influenza B strains in Zhuhai reached the peak of isolation in August, later than the peak of isolation of influenza A strains in July and peaked in April in early April, earlier than the peak of separation of influenza A strains May. In 2008-2009 Zhuhai popular influenza B virus dominant strains of Victoria virus. Compared with the northern hemisphere international vaccine strain B / Florida / 4/2006 like-virus (GenBank serial number CY033876.1), there were 7 amino acid substitutions in the HA1 fragment of influenza A virus of Yamagata strain in Zhuhai during 2008-2009 : 103 K → R, 212 D → N, respectively, in which 218 N → S of 08-1267, 09-0233 and 09-0240 strains and 123 P → A, 245 S → G and 270 P → S of 08-190 strains 181N → Y, 245S → D of the other 5 strains of 08-190, the amino acid homology was higher than 97%. Two of these amino acid substitutions involved in the epitope formation were replaced without viral antigen drift. Victoria strains have less than 89% homology with vaccine-representative strains. Conclusion The prevalence of influenza A virus of Yamagata strain in Zhuhai between 2008 and 2009 was highly homologous to that of the vaccine. This year, the influenza vaccine strain played a role in the epidemic prevention and control of influenza B virus in Zhuhai. In 2008-2009 Zhuhai prevalence of influenza B virus strains are Victoria, so this year’s influenza vaccine strains can not provide the best protection of the epidemic of influenza B in Zhuhai. Zhuhai City, 2008 influenza B influenza epidemic longer, the peak in 2009 may be related to this peak.