Novel genetic reassortants in H9N2 influenza A viruses and their diverse pathogenicity to mice.
Novel genetic reassortants in H9N2 influenza A viruses and their diverse pathogenicity to mice.
复制标题
H9N2甲型流感病毒的新基因重配及其对小鼠的不同致病性
DOI：
10.1186/1743-422x-8-505
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发表时间：
2011-11-04
期刊：
影响因子：
4.8
通讯作者：
Liu W
中科院分区：
文献类型：
--
作者：
Bi Y;Lu L;Li J;Yin Y;Zhang Y;Gao H;Qin Z;Zeshan B;Liu J;Sun L;Liu W
H9N2型甲型流感病毒在不同的宿主物种中经历了广泛的重组，可能导致流行或大流行，并有可能出现新的病毒。方法为了解早期和当前流行的H9N2病毒的基因和致病特性，对1998年至2010年从中国北部病鸡中分离的15株代表性H9N2病毒进行了鉴定，并与NCBI数据库中的所有中国H9N2病毒进行了比较。结果15株分离株中大部分为重配株，产生了4种新的基因类型(B62-B65)，它们整合了欧亚H9N2亚型、北美H9N2亚型和H5N1亚型的基因片段。值得注意的是，新发现的B65基因型自2007年以来一直在中国中流行，更重要的是，不同的H9N2型流感病毒对小鼠表现出不同的致病性。2008-2010年疫情分离株(B55和B65)的传染性较弱，而20世纪90年代末分离的两株具有代表性的B0和G2型病毒对小鼠具有高致病性。此外，Ck/SD/LY-1/08(63型，含有类H5N1 NP和PA基因)在小鼠肺内复制良好，病毒滴度高，但临床症状轻微。结论多条证据表明，H9N2型流感病毒不断改变其基因和致病性。因此，应密切监测H9N2病毒的遗传进化及其对哺乳动物的致病性，以防止新的大流行病毒的出现。
BackgroundH9N2 influenza A viruses have undergone extensive reassortments in different host species, and could lead to the epidemics or pandemics with the potential emergence of novel viruses.MethodsTo understand the genetic and pathogenic features of early and current circulating H9N2 viruses, 15 representative H9N2 viruses isolated from diseased chickens in northern China between 1998 and 2010 were characterized and compared with all Chinese H9N2 viruses available in the NCBI database. Then, the representative viruses of different genotypes were selected to study the pathogenicity in mice with the aim to investigate the adaptation and the potential pathogenicity of the novel H9N2 reassortants to mammals.ResultsOur results demonstrated that most of the 15 isolates were reassortants and generated four novel genotypes (B62-B65), which incorporated the gene segments from Eurasian H9N2 lineage, North American H9N2 branch, and H5N1 viruses. It was noteworthy that the newly identified genotype B65 has been prevalent in China since 2007, and more importantly, different H9N2 influenza viruses displayed a diverse pathogenicity to mice. The isolates of the 2008-2010 epidemic (genotypes B55 and B65) were lowly infectious, while two representative viruses of genotypes B0 and G2 isolated from the late 1990s were highly pathogenic to mice. In addition, Ck/SD/LY-1/08 (genotype 63, containing H5N1-like NP and PA genes) was able to replicate well in mouse lungs with high virus titers but caused mild clinical signs.ConclusionSeveral lines of evidence indicated that the H9N2 influenza viruses constantly change their genetics and pathogenicity. Thus, the genetic evolution of H9N2 viruses and their pathogenicity to mammals should be closely monitored to prevent the emergence of novel pandemic viruses.