2006年河北省新分离Victoria系B型流感病毒变异株血凝素基因序列分析

Molecular and Phylogenetic Analysis of Haemagglutinin Sequences From Influenza B Isolates in Hebei Province in 2006

目的分析2006年河北省分离的B型流感毒株HA抗原性和基因特性,阐明HA基因的变异与流感流行的关系。方法用MDCK(Madin Darby Canine Kidney)细胞分离培养流感病毒,血凝抑制(Hemasslutination Inhibition,HI)试验鉴定型别。提取病毒核糖核酸(RNA),采用RT-PCR扩增病毒HA基因,纯化产物进行核苷酸序列测定,用DNAStar软件作分析处理。结果2006年在河北省流行的B型流感病毒属Victoria系,与北半球该流行期的国际疫苗株B/上海/361/02不同,其抗原性与最近的Victoria系代表株B/Hong Kong/330/2001相比已发生较大变异,核苷酸同源性仅为96.5%～97.2%,在抗原决定簇上有6个位点发生了氨基酸替换。结论2006年在河北省流行的Victoria系B型流感病毒是一个新的变种,在HA1区域发生的变异是今年B型流感流行的主要原因,应该引起重视。

Objective To analyze the characteristics of HA1 gene of influenza B isolated from Hebei Province in 2006, and to elucidate the relationship between the influenza epidemic and the variation of HA1 region of the virus. Methods The viruses were isolated and propagated by MDCK cell. RNAs were extracted and their HA1 genes were amplified by reverse transcription polymerase chain reaction （RT- PCR）. The purified PCR products were sequenced. The data obtained were analyzed by the software DNAStar. Results The influenza B viruses from Hebei Province in 2006 were Victoria like strain, which were different from the B/Shanghai/361/2002, Yamagata- like- virus. Comparing to the B/Hong Kong/330/2001 virus, they had an identity of 96..5 % --97.2 % in nucleotide sequence, Which were far away from B/Hong Kong/330/2001 in the phyiogenic tree, and six variant amino acids were found locating in antigenic determinant sites. Conclusion The influenza B viruses in Hebei Province in 2006 occurred evident antigenic drift in HAl region, which caused the influenza t3 epidemic and outbreak in Hebei Province during the. period of 2005. They are new variants and should be paid close attention.