2006年河北省流感爆发中分离Victoria系乙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 the influenza outbreaks in Hebei Province in 2006

目的研究2006年河北省流感爆发中分离的乙型流感毒株HA抗原性和基因特性,阐明HA基因的变异与流感爆发的关系。方法用MDCK细胞分离培养流感病毒,提取病毒核糖核酸,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年在河北省流感爆发中分离的乙型流感病毒属Victoria系,与最近的代表株B/HongKong/330/2001相比已发生较大变异,核苷酸同源性仅为96.4%～96.8%,在抗原决定簇上有6～7个位点发生了氨基酸替换,与流感监测中分离的Victoria系乙型流感病毒HA1区改变一致。结论2006年河北省流感爆发与常规监测中分离到的乙型流感病毒HA1抗原性改变一致,是Victoria系乙型流感病毒的一个新变种,在HA1区域发生的变异是乙型流感爆发的主要原因,应引起重视。

Objective In order to study the characteristics of HA1 gene of influenza B isolated from the influenza outbreak in Hebei Province in 2006, and to elucidate the relationship between the influenza epidemic/outbreak and the variation of HA1 region of the virus. Methods The viruses were isolated and propagated by MDCK. 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 with the software DNAStar. Results The influenza B viruses isolated from the influenza outbreak in Hebei province during 2006 are Victoria like strain, is different from the B/Shanghai/361/2002, the later is Yarnagata-like-virus, but being similar to the epidemic isolates. Comparing to the B/Hong Kong/330/2001 virus, they had an identity of 96.4% ～96.8% in nucIeotide sequence, and far away from B/Hong Kong/330/2001 in phylogenic tree, 6～7 variant amino acids were found 10- cating in determinant sites. Conelusions The antigenic drift in HA1 region of the influenza B viruses isolated from the outbreaks and the influenza surveillance in Hebei Province in 2006 are similar, which is the fundamental cause of the influenza outbreak and form a new variant.