人群中流行的H1N1病毒按其来源可分为两类:人感染的猪H1N1病毒与人类季节性H1N1流感病毒.这两类病毒在流行频率、易感性和致病性等方面存在明显差异.文章收集了1918～2009年间17株人感染的猪甲型H1N1毒株以及21株季节性H1N1毒株,通过序列比对、氨基酸残基保守性分析及3D结构对比等生物信息学方法,揭示造成这两类病毒流行病学和感染性差异的机制.研究发现这两类病毒HA蛋白的进化路径并不相同,且两者具有不同的突变特征,人感染的猪H1N1病毒中,Ca1、Ca2、Sa和Sb四个位点均较为保守,仅Cb位点的突变较快；季节性H1N1病毒仅有Ca1位点较为保守,其他四个抗原性位点均具有较快的突变速率,且较多的突变为新类型的氨基酸.另外,对受体结合位点的研究也显示,这两类病毒的该区域存在5个氨基酸水平的差异(ALA138SER、GLN192LYS、GLN196HIS、ALA198GLU和ALA227GLU),这些位点的差异使得人感染的猪H1N1流感病毒比人类季节性H1N1病毒的易感性更强.这些研究结果可为阐明两类H1N1流感病毒感染性及致病性差异提供更多的信息,并有助于进一步认识H1N1流感病毒的进化机制.%There are two kinds of H1N1 viruses circulating in human population, human infection swine H1N1 and human seasonal H1N1 viruses, showing different prevalent frequency and infectivity. In this work, in order to illustrate their different prevalent characteristics, 17 HA sequences for human infection swine H1N1 and 21 for human seasonal H1N1 viruses were collected. Bioinformatical method, such as sequence alignment, amino acid conservation analysis and 3D structure comparison were used to reveal the mechanism for their difference. The results suggest that different mutation features for HA epitope sites of these two H1N1 viruses. For human infection swine H1N1, Ca1, Ca2, Sa and Sb sites are more conserved, while Cb site is more variable. But for human seasonal H1N1, only Ca1 site is conserved, other four sites are more variable and show more variety mutants. In addition, research on receptor binding sites revealed 5 amino acid differences (ALA138SER, GLN192LYS, GLN196HIS, ALA198GLU and ALA227GLU). These results provide information for illustrating the diverse pathogenesis and infectivity between human infection swine H1N1 and human seasonal H1N1 viruses, and can further help understanding the mutation of H1N1 viruses.
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