Cui Mingxian, Huang Yanming, Wang Xingbo, Bian Xiyi, Du Liuyang, Yan Yan, Gu Jinyan, Dong Weiren, Zhou Jiyong, Liao Min
MOA Key Laboratory of Animal Virology, Department of Veterinary Medicine and Center of Veterinary Medical Sciences, Zhejiang University, Hangzhou, China.
Collaborative Innovation Center and State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University, Hangzhou, China.
Front Microbiol. 2022 Aug 1;13:963218. doi: 10.3389/fmicb.2022.963218. eCollection 2022.
H6-subtype avian influenza virus (AIV) was prevalent in the world and could sporadically infect humans. Here, a new chicken-derived H6N6-subtype AIV strain A/chicken/Zhejiang/49/2021 (ZJ49) was isolated in Zhejiang Province, China in 2021. Phylogenetic analysis by Maximum likelihood methods showed that H6-subtype AIVs were classed into 13 groups according to HA gene. The ZJ49 strain belonged to the G12 group, which mainly consisted of strains from Asian and dominated in recent years. Based on NA gene, H6-subtype AIVs were divided into N6.1 and N6.2 clades according to the NA gene. The ZJ49 isolate was located in the N6.2e clade, which mainly consisted of the H5N6-subtype AIVs. Phylogenetic analysis by Bayesian methods showed that the effective quantity size of H6-subtype AIVs increased around 1990, reached a peak around 2015, declined after 2015, then kept in a stable level after 2018. The reassortment analysis predicted that the PB2, PA, and NA genes of ZJ49 may recombine with H5-subtype AIVs. The amino acid at 222 position of HA gene of ZJ49 strain mutated from A to V, suggesting that ZJ49 has a potential ability to cross species barriers. The four glycosylation sites were highly conserved, implying less impact on the fold and conception of HA stem structure. Our results revealed the complicated evolution, reassortment, and mutations of receptor binding sites of H6-subtype AIVs, which emphasize the importance to continuously monitor the epidemiology and evolution of H6-subtype AIVs.
H6亚型禽流感病毒（AIV）在全球广泛流行，且可偶尔感染人类。在此，2021年在中国浙江省分离出一株新的源自鸡的H6N6亚型AIV毒株A/鸡/浙江/49/2021（ZJ49）。采用最大似然法进行系统发育分析表明，根据血凝素（HA）基因，H6亚型AIV可分为13个组。ZJ49毒株属于G12组，该组主要由亚洲毒株组成且近年来占主导地位。基于神经氨酸酶（NA）基因，H6亚型AIV根据NA基因分为N6.1和N6.2分支。ZJ49分离株位于N6.2e分支，该分支主要由H5N6亚型AIV组成。采用贝叶斯方法进行系统发育分析表明，H6亚型AIV的有效数量规模在1990年左右增加，在2015年左右达到峰值，2015年后下降，然后在2018年后保持稳定水平。重配分析预测，ZJ49的PB2、PA和NA基因可能与H5亚型AIV发生重配。ZJ49毒株HA基因第222位氨基酸由A突变为V，表明ZJ49具有跨物种屏障的潜在能力。四个糖基化位点高度保守，意味着对HA茎结构的折叠和构象影响较小。我们的结果揭示了H6亚型AIV受体结合位点的复杂进化、重配和突变，这强调了持续监测H6亚型AIV流行病学和进化的重要性。
