广州2006年乙型流感病毒血凝素和神经氨酸酶基因特性分析

An Analysis on Genetic Characteristics of Hemagglutinin and Neuraminidase of Type B Influenza Viruses in Guangzhou in 2006

为了解2006年广州地区流行的乙型流感病毒株血凝素（HA）和神经氨酸酶（NA）的基因特性，选择病原学监测病毒株和暴发性疫情病毒株，提取病毒RNA并逆转录为cDNA，通过PCR方法扩增乙型流感病毒HA和NA全长基因，将扩增的DNA片段接入T—A克隆载体进行测序，并使用DNAStar软件对测序结果进行分析。结果显示：不同来源的流感病毒株HA的同源性为99％以上，都属于Victoria系；不同来源的病毒株NA同源性为98％以上。HA和NA的种系发生树分析表明：病原学监测毒株同源性更接近，而暴发性疫情毒株的同源性则相对较为分散。所有毒株与WHO推荐的2005-2006年度疫苗株B／Shanghai／361／2002的同源性只有88．9％～89．7％，说明该年度的流感疫苗对乙型流感不能提供最佳的保护。

To understand the genetic characteristics of hemagglutinin（HA） and neuraminidase（NA） of type B influenza viruses in Guangzhou in 2006, three virus strains from etiology surveillance and seven strains from outbreaks were investigated. Genome RNAs of type B influenza viruses were extracted and reverse-transcripted into cDNAs using random primers. The whole-length DNA of HA and NA were amplified by polymerase chain reaction （PCR）, cloned into T-A plasmid and sequenced, and analyzed phylogenetically by DNAstar software. The results showed that the HA of type B influenza viruses were similar and the homology were more than 99%. The type B influenza viruses belong to Victoria lineage. The NA of the type B influenza viruses were similar and the homology were more than 98%. Phylogenetic trees of HA and NA showed that the isolates from etiology surveillance formed a cluster, and the isolates from outbreaks were separated from the cluster. The homology of the type B influenza viruses with B/Shanghai/361/2002, which is the WHO recommended influenza vaccine strain in 2005-2006, were 88.9%-89.7%. It suggested the protective effect of influenza vaccine against type B influenza viruses used in 2005-2006 in Guangzhou may not be afforded.