一株人源H1N1亚型猪流感病毒的进化分析与生物学特性研究

Evolution analysis and biological characteristics of a human origin H1N1 subtype swine influenza virus

为了解猪流感病毒(SIV)的变异情况,我们2009年11月从河北某养殖场采集呈流感症状的猪鼻拭子40份,接种10日龄SPF鸡胚,分离到一株猪流感病毒,通过RT-PCR和血凝抑制试验鉴定为H1N1亚型,命名为A/swine/Hebei/15/2009(H1N1),其全基因序列测定及同源性分析发现,8个基因片段均与2000年左右H1N1人流感病毒有较高的同源性。系统遗传演化显示,该病毒分离株是由2000年人源H1N1流感病毒A/Dunedin/2/2000(H1N1)进化而来。抗原性分析显示该株与甲型H1N1流感病毒和经典H1N1病毒株抗原性差异较大。对小鼠致病性试验表明该病毒株可以直接感染小鼠并导致小鼠轻微临床症状和组织病理学变化,但不致死小鼠,表现为低致病性。

To isolate the swine influenza virus（SIV）,a total of 40 nasal swabs samples were collected from pigs which had influenza like symptoms in Hebei province in November,2009.A virus was isolated by inoculation of 10-day-old embryonated eggs via allantoic cavities and identified as H1N1 subtype by hemagglutination inhibition（HI） test and RT-PCR,designated A/Swine/Hebei/15/2009（H1N1）.The complete genes were sequenced and the results shown that the eight gene segments of the isolate were closely identical to human H1N1 influenza virus A/Dunedin/2/2000（H1N1）.The genetic analysis indicated that the virus was directly derived from the human H1N1 influenza virus.HI tests found that the isolate had less cross reaction with the reference strains of pandemic H1N1 or classical swine H1N1.In addition,the pathogenic tests in mice demonstrated the virus was able to infect the mice directly and cause less clinical sings and histopathologic change,but no mortality occurred.