广东省2003年甲_3型流行性感冒病毒血凝素重链区基因的特征

Characteristics of HA_1 Gene of Influenza A(H_3N_2)Viruses Circulated in Guangdong in 2003.

目的了解广东省2003年甲型流行性感冒(流感)病毒的抗原变异情况和血凝素重链区(HA1)基因的特征.方法对广东省流感分子流行病学资料进行分析.结果全年分离到481株甲型流感病毒,全部是H3N2亚型,其抗原性与疫苗株甲/马拿马/2007/99(H3N2)有所不同,类似于疫苗变异株甲/福建/411/02(H3N2).在HA1区氨基酸序列上,与疫苗株甲/巴拿马/2007/99(H3N2)存在25～30个氨基酸的差异,同源性为92.1%.抗原决定族A、B、D、E区以及受体结合部的左侧臂和前臂均发生氨基酸替换,并在144位增加了1个糖基化位点.结论广东省2003年甲3型流感活动比2002年进一步加强,与疫苗株相比,病毒基因发生突变,抗原性发生了漂移.

Objective To understand antigenic and genetic characteristics of HA1 gene of influenza A circulated in Guangdong in 2003. Method The data of influenza molecular surveillance were analyzed. 481 influenza A（H3N2） viruses were isolated. Most of influenza A （H3N2） viruses were antigenically distinct from vaccine strain A/Panama/2007/99 （H3N2）, and similar to a drift variant stain, A/Fujian/411/02 （ H3 N2）. Compared with vaccine strain A/Panama/2007/99 （ H3 N2）, there were 25 -30 amino acid substituted on HA1 protein, and the homology of amino acid sequence was only 92.1%. These changes located in antigenic determinant A,B, D, and E, and also in the left and front side of the receptor-binding site. At 144 position, amino acid I→N change would add a N-linked glycosylation site; the research shows that Guangdong influenza （H3N2） activity in 2003 was more severe than in 2002, and the antigenic drift of influenza （H3N2） has occurred.