2001年中国新分离维多利亚系乙型流感病毒的抗原性及基因特性分析

目的：研究2001年中国新分离维多利亚（Victoria)系乙型流感病毒的抗原性及基因特性。方法：鸡胚传代流感病毒，从尿囊液中提取流感病毒的RNA，进行逆转录－聚合酶链反应（RT－PCR），扩增产物用纯化试剂盒纯化后测序，然后用MegAlign软件进行基因种系发生树分析。结果：B／Sichuan/63/2001和B／Zhejiang/2/2001毒株的抗原性与B／Shandong/7/97毒株间存在有差异，编码血凝素重链区基因已发生了突变并导致了HA1蛋白抗原性表位两个位点（197和199）氨基酸不同于B／Shandong/7/97毒株，基因种系发生树分析同样也证明了它们的HA1基因不同于B／Shandong/7/97病毒。然而，B／Sichuan/63/2001与B／Zhejiang/2/2001毒株间无论抗原性还是HA1基因特性均很相似。结论：2001年我国人群中流行的乙型流感病毒维多利亚毒株系的抗原性已发生进一步的漂移。

Antigenic and genetic characterizations of Victoria like strain of influenza B viruses isolated in China in 2001

Objective To understand the antigenic and genetic characteristics of Victoria like strain of influenza B virus isolated recently and to provide a scientific evidence for influenza surveillance and monitoring of influenza epidemic in future. Methods Viruses were passed in embryonated hen eggs and virion RNA was extracted from allantoic fluid and reverse transcribed to synthesize cDNA. cDNA was amplified by PCR and the PCR product was purified with a purification kit. Afterwards RNA sequence analysis was performed by dideoxynucleotide chain termination and a cloning method. Finally, phylogenetic analysis of the sequencing data was performed with MegAlign. Results B/Sichuan/63/2001 and B/Zhejiang/2/2001 viruses were antigenically different from B/Shandong/7/97 strain. The substitution of nucleotide sequences of HA1genes of them compared with those of B/Shandong/7/97strainresulted in the change of amino acid sequences in antigenic determinants on HA1 protein domain. The phylogenetic analysis also indicated that strains isolated recently were genetically different from B/Shandong/7/97/strain. However, there was neither differences on the antigenicity nor genetic partern between these two isotates.Conclusion The antigenic drift of Victoria like strain of influenza B virus isolated recently in China has further occurred.