Enhanced pathogenicity and transmissibility of H9N2 avian influenza virus in mammals by hemagglutinin mutations combined with PB2-627K  

作　　者：Kaituo Liu Yaqian Guo Huafen Zheng Zhuxing Ji Miao Cai Ruyi Gao Pinghu Zhang Xiaowen Liu Xiulong Xu Xiaoquan Wang Xiufan Liu 

机构地区：[1]Joint International Research Laboratory of Agriculture and Agri-Product Safety,The Ministry of Education of China,Yangzhou University,Yangzhou,225009,China [2]Animal Infectious Disease Laboratory,College of Veterinary Medicine,Yangzhou University,Yangzhou,225009,China [3]Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonosis,Yangzhou University,Yangzhou,225009,China [4]Jiangsu Key Laboratory of Zoonosis,Yangzhou,225009,China [5]Institute of Translational Medicine,Key Laboratory of Geriatric Disease Prevention and Control of Jiangsu Province,Medical College,Yangzhou University,Yangzhou,225009,China

出　　处：《Virologica Sinica》2023年第1期47-55,共9页中国病毒学（英文版）

基　　金：supported by the National Key Research and Development Project of China:2021YFD1800202;by the National Natural Science Foundation of China:31772755,32072892,32072832;by the Earmarked Fund for China Agriculture Reasearch System:CARS-40;by the Priorty Academic Program Development of Jiangsu Higher Education Institutions(PAPD).

摘　　要：H9N2 avian influenza viruses(AIVs)circulate globally in poultry and have become the dominant AIV subtype in China in recent years.Previously,we demonstrated that the H9N2 virus(A/chicken/Eastern China/SDKD1/2015)naturally harbors a mammalian-adaptive molecular factor(627K)in the PB2 protein and is weakly pathogenic in mice.Here,we focused on new markers for virulence in mammals.A mouse-adapted H9N2 virus was serially passaged in mice by infecting their lungs.As expected,infected mice showed clinical symptoms and died at passage six.A comparison between the wild-type and mouse-adapted virus sequences identified amino acid substitutions in the hemagglutinin(HA)protein.H9N2 viruses with the T187P t M227L double mutation exhibited an increased affinity to human-type(SAα2,6Gal)receptors and significantly enhanced viral attachment to mouse lung tissues,which contributed to enhancing viral replication and virulence in mice.Additionally,HA with the T187P t M227L mutation enabled H9N2 viral transmission in guinea pigs via direct contact.AIV pathogenicity in mice is a polygenic trait.Our results demonstrated that these HA mutations might be combined with PB2-627K to significantly increase H9N2 virulence in mice,and this enhanced virulence was achieved in other H9N2 AIVs by generating the same combination of mutations.In summary,our study identified novel key elements in the HA protein that are required for H9N2 pathogenicity in mice and provided valuable insights into pandemic preparedness against emerging H_(9)N_(2)strains.

关 键 词：H9N2 Hemagglutinin(HA) PB2-627K Mammalian adaptation PATHOGENICITY TRANSMISSIBILITY 

分 类 号：S852.65[农业科学—基础兽医学]