甲型H1N1流感重症患者病毒血凝素和神经氨酸酶基因特性分析

目的 通过分析2009-11-02～12-04期间北京市6例甲型H1N1流感重症患者咽拭子中病毒的血凝素、神经氨酸酶基因特性,了解其基因进化特点,以期对下一步甲型H1N1流感的防控和重症的治疗提供理论依据.方法 使用实时荧光PCR方法,检测重症患者样本为甲型H1N1流感病毒阳性样本,利用测序引物扩增血凝素、神经氨酸酶基因,测定核苷酸序列,利用生物信息软件拼接序列;分析重要基因位点,对其进行基因进化、耐药性分析.结果 6件测定样本血凝素、神经氨酸酶基因与疫苗株A/California/07/2009(H1N1)核苷酸、氨基酸的同源性分别为99.2%及99.5%,有8个血凝素基因的氨基酸发生替换,为65、100、145、185、216、220、338及391位,其中145位位于抗原决定簇A区,220位位于抗原决定簇D区,同时是受体结合位点的后壁;有5个神经氨酸酶基因的氨基酸发生了替换,为59、106、232、248及365位,其中106、232、248位位于酶活性区域;未发生神经氨酸酶基因275位H→Y的替换.结论 北京市甲型H1N1流感重症患者病毒血凝素和神经氨酸酶基因与疫苗株A/California/07/2009(H1N1)高度同源,部分血凝素基因、神经氨酸酶基因有氨基酸替换,但其作用不清.所有测定样本未发生对达菲类药物的耐药性突变.

Genetic analysis for haemagglutinin and neuraminidase gene of novel influenza virus A (H1N1)from severe cases in Beijing

Objective To analyze the genetic characteristics of novel influenza virus A (H1N1)from severe cases in Beijing.Methods 6 swabs from severe eases infected by pandemic influenza virus A (H1N1) were selected and were confirmed by real -time PCR firstly.The HA and NA complete gene of those samples were then sequenced in order to analyze the gene characteristics.Results Compared to A/California/07/2009(H1N1) ,the international reference strain in 2009, the genetic homology of HA and NA complete gene in the 6 samples were 99.2% for nucleotide and 99.5% for protein respectively.There were some shifts of amino acids in some samples.The amino positions were 65,100,145,185,216,220,338,391 for HA gene, while 59, 106, 232, 248,365 for NA gene.145 of HA gene was located in the antigenic site A, while 220 in the site D and 220 was the RBS site at the same time.106,232,248 of NA gene were located in the neuraminidase activity site.No mutations of 275 in NA gene were found.Conclusion The HA and NA gene of novel influenza virus A (H1N1) from severe cases in Beijing were highly homologous with the reference strain A/ California/07/2009(H1N1).Some mutations in the two genes were found but their functions were not clear.All the samples were sensitivity to oseltamivir.