一株H6N6亚型野鸟禽流感病毒全基因组序列分析以及对小鼠的感染性研究

The complete genomic sequence and infectivity analysis of a wild bird-derived H6N6 subtype avian influenza virus

为进一步了解2015年分离于我国新疆野鸟粪便中的一株H6N6亚型禽流感病毒(AIV)A/WB/XJ/S1541/2015(H6N6)的生物学特性,本研究对其进行了全基因组测序、遗传演化分析以及BALB/c小鼠的感染性试验。序列分析结果显示:该分离株HA蛋白裂解位点的氨基酸序列为^(339)PQIETR↓GL^(346),仅有1个碱性氨基酸,具有低致病性AIV的分子特征。此外,分离株表面基因HA、NA均与一株H6N6亚型猪流感病毒A/swine/Guangdong/K6/2010高度同源,而内部基因均与H6N6亚型AIV A/pigeon/Guangxi/161/2014(H6N6)高度同源,提示该分离株基因来源的多样性。小鼠的感染性试验结果显示:该病毒可在小鼠的肺脏和鼻甲中有效复制,病毒滴度分别为5.33 log_(10) EID_(50)/mL、4.50 log10EID50/m L,提示其具有感染哺乳动物的潜在风险。本研究结果为H6亚型AIV的持续性监测和相关生物学特性的研究奠定基础。

To investigate the biological characteristic of an H6N6 subtype avian influenza virus （AIV） collected in Xingjiang province in 2015. The complete genome was sequenced, the evolutionary relationship was analyzed and the pathogenicity of the isolate was evaluated in BALB/c mice. The amino acid sequence analysis of the virus showed that the cleavage site between HA1 and HA2 was 339PQIETR↓GL346, and it only had one basic amino acid at HA cleavage site, which was a typical characteristic of low-pathogenicity AIV. The surface genes of this isolate had the highest nucleotide sequence similarity to A/swine/Guangdong/ K6/2010, while the internal genes had the highest nucleotide sequence similarity to A/pigeon/Guangxi/161/2014（H6N6）, which showed the isolate had distinct genetic diversity. The pathogenicity of the virus in mice suggested that the isolate was capable of replication in mouse lung and nasal turbinate without prior adaptation. The virus titers in lung and nasal turbinate were 5.33 log10 EID50/mL, 4.50 log10 EID50/mL, respectively, suggesting it posed a potential risk to infect mammals. Thus, the results of this study lay the foundation for the continuous monitoring and the biological characteristic study of H6 avian influenza virus.