河北省2004～2008年乙型流行性感冒病毒监测与血凝素蛋白基因序列分析

Virological Surveillance and Molecular Characteristics of Influenza B Viruses in Hebei Province During 2004-2008

目的了解河北省2004～2008年乙型流行性感冒(流感)病毒抗原性的变异及种系分布。方法采用狗肾传代细胞分离流感病毒,经血清学鉴定后提取病毒核糖核酸,经逆转录-聚合酶链反应扩增目的基因后,进行乙型流感病毒的血凝素重链(Heamagglutining1HA1)基因片段的核苷酸序列测定。结果2004年10月～2008年3月,共分离到乙型流感病毒131株,其中48株为维多利亚(Victoria)系,83株为山形(Yamagata)系。2004～2005年流行期为Yamagata系毒株,2005～2006年流行期为Victoria系毒株,2006～2008年2个流行期都有Yamagata和Victoria系的毒株出现。HA1基因片段核苷酸序列测定结果显示,两个系列的毒株都有小的变异,但Yamagata系毒株变异更明显。2008年分离到的Yamagata系乙型流感病毒与2005年毒株相比已经有8个氨基酸被替代,同源性只有97.4%～98.0%。结论2004～2008年Victoria系乙型流感病毒的抗原性未发生明显的变异,但Yamaga-ta系乙型流感病毒的基因发生变异,使抗原性发生漂移,是2007～2008年流行期引起乙型流感爆发的主要因素。

Objective To understand influenza B viruses circulating and antigenic variation and distributing in Hebei province during 2004-2008. Methods Viruses were isolated with Madin-Darby canine kidney（MDCK）cells. Viral RNA was extracted from isolates after serological identification and transcribed into cDNA by reverse transcript and ampified by PCR. The PCR product was purified and nucleotide sequence of HA1 gene of the influenza B viruses was analyzed. Resuits 131 influenza B viruses were obtained from October 2004 to March 2008. Among them,48 strains were Victoria-lineage and 83 strains were Yamagata-lineage viruses. Yamagata-lineage viruses were detected in the 2004- 2005, replaced by Victoria-lineage viruses in the 2005- 2006. Both Victoria-lineage and Yamagata-lineage viruses were isolated in 2006--2007 and 2007-- 2008. There were several amino ack s substitution in both Victoria and Yamagata lineages accord- ing to the result of sequence analysis of the hemagglutinin HA1 genes, and Yamagata lineages viruses took more frequently substitution in isolates. Influenza B viruses in 2008 were differed by 8 amino acids from virus stains, in 2005with homology of 97.4%--98.0%. Conclusion The anti- genicity of Victoria-lineage virus didn＇t take place varidation apparently in Hebei provinece during 2004--2008, but Yamagata-lineage virus took drift and caused outbreak of influenza in the epidemic season of 2007--2008.