禽流感H9N2病毒与H1N1流感病毒很容易发生重排

2月28日，中国农业大学动物医学院刘金华教授课题组在《美国国家科学院院刊》杂志在线发表。这是刘金华教授课题组于2005年在Science、2007年在Lancet等国际权威杂志发表文章以来，取得的又一项重要研究成果。

猪源H1N1/2009流感病毒自2009年爆发以来，在世界范围迅速传播，给人类健康造成了严重威胁。重排是流感病毒进化的主要方式之一，历史上多次流感的流行都是病毒重排的结果。中国农业大学动物医学院刘金华教授课题组研究的成果表明：禽流感H9N2病毒与H1N1流感病毒很容易发生重排，且部分重排病毒的毒力明显提高。昨日，这一成果在线发表于PNAS，动物医学院农业部人畜共患病重点实验室孙怡朋博士为第一作者、刘金华教授为通讯作者。

H9N2亚型流感病毒是家禽中的主要流感病毒亚型，不少报道证实了禽H9N2流感病毒可以跨种间感染与传播到猪和人。H1N1病毒已在人群中持续流行，且已在猪群中存在。因此，此两种亚型的病毒在自然界有着很大的机会发生重排。

刘金华教授课题组利用反向遗传操作技术和小鼠模型对H1N1病毒和禽H9N2病毒的重排性开展了研究。他们发现，这两种病毒极易发生重排，重排病毒容易感染小鼠且部分重排病毒较两株亲本病毒致病力明显提高。通过对强毒力重排病毒基因组分析发现，所有强毒力病毒的PA基因均来自于H1N1流感病毒。

这一结果为未来流感病毒的防控提供了重要的理论参考。研究结果提示，在流感监控中应重视新型重排病毒的产生，尤其是那些携带有H1N1源PA基因的重排病毒。（生物谷Bioon.com）

生物谷推荐原文出处：

PNAS   doi: 10.1073/pnas.1019109108

High genetic compatibility and increased pathogenicity of reassortants derived from avian H9N2 and pandemic H1N1/2009 influenza viruses

Yipeng Suna,1, Kun Qinb,1, Jingjing Wanga, Juan Pua, Qingdong Tanga, Yanxin Hua, Yuhai Bia,c, Xueli Zhaoa, Hanchun Yanga, Yuelong Shub, and Jinhua Liua,d,2

Abstract

H9N2 influenza viruses have been circulating worldwide in multiple avian species and repeatedly infecting mammals, including pigs and humans, posing a significant threat to public health. The coexistence of H9N2 and pandemic influenza H1N1/2009 viruses in pigs and humans provides an opportunity for these viruses to reassort. To evaluate the potential public risk of the reassortant viruses derived from these viruses, we used reverse genetics to generate 127 H9 reassortants derived from an avian H9N2 and a pandemic H1N1 virus, and evaluated their compatibility, replication ability, and virulence in mice. These hybrid viruses showed high genetic compatibility and more than half replicated to a high titer in vitro. In vivo studies of 73 of 127 reassortants revealed that all viruses were able to infect mice without prior adaptation and 8 reassortants exhibited higher pathogenicity than both parental viruses. All reassortants with higher virulence than parental viruses contained the PA gene from the 2009 pandemic virus, revealing the important role of the PA gene from the H1N1/2009 virus in generating a reassortant virus with high public health risk. Analyses of the polymerase activity of the 16 ribonucleoprotein combinations in vitro suggested that the PA of H1N1/2009 origin also enhanced polymerase activity. Our results indicate that some avian H9-pandemic reassortants could emerge with a potentially higher threat for humans and also highlight the importance of monitoring the H9-pandemic reassortant viruses that may arise, especially those that possess the PA gene of H1N1/2009 origin.