Antibodies elicited by Newcastle disease virus-vectored H7N9 avian influenza vaccine are functional in activating the complement system  

作　　者：Zenglei Hu Ya Huang Jiao Hu Xiaoquan Wang Shunlin Hu Xiufan Liu 

机构地区：[1]Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China,Yangzhou University,Yangzhou 225009,China [2]Animal Infectious Disease Laboratory,School of Veterinary Medicine,Yangzhou University,Yangzhou 225009,China [3]Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses,Yangzhou University,Yangzhou 225009,China

出　　处：《Journal of Integrative Agriculture》2024年第6期2052-2064,共13页农业科学学报（英文版）

基　　金：supported by the earmarked fund for China Agriculture Research System(CARS-40);the Key Research and Development Project of Yangzhou(Modern Agriculture),China(YZ2022052);the‘‘High-end Talent Support Program’’of Yangzhou University,China。

摘　　要：H7N9 subtype avian influenza virus poses a great challenge for poultry industry.Newcastle disease virus(NDV)-vectored H7N9 avian influenza vaccines(NDV_(vec)H7N9)are effective in disease control because they are protective and allow mass administration.Of note,these vaccines elicit undetectable H7N9-specific hemagglutination-inhibition(HI)but high IgG antibodies in chickens.However,the molecular basis and protective mechanism underlying this particular antibody immunity remain unclear.Herein,immunization with an NDV_(vec)H7N9 induced low anti-H7N9 HI and virus neutralization titers but high levels of hemagglutinin(HA)-binding IgG antibodies in chickens.Three residues(S150,G151 and S152)in HA of H7N9 virus were identified as the dominant epitopes recognized by the NDV_(vec)H7N9 immune serum.Passively transferred NDV_(vec)H7N9 immune serum conferred complete protection against H7N9 virus infection in chickens.The NDV_(vec)H7N9 immune serum can mediate a potent lysis of HA-expressing and H7N9 virus-infected cells and significantly suppress H7N9 virus infectivity.These activities of the serum were significantly impaired after heat-inactivation or treatment with complement inhibitor,suggesting the engagement of the complement system.Moreover,mutations in the 150-SGS-152 sites in HA resulted in significant reductions in cell lysis and virus neutralization mediated by the NDV_(vec)H7N9 immune serum,indicating the requirement of antibody-antigen binding for complement activity.Therefore,antibodies induced by the NDV_(vec)H7N9 can activate antibody-dependent complement-mediated lysis of H7N9 virus-infected cells and complement-mediated neutralization of H7N9 virus.Our findings unveiled a novel role of the complement in protection conferred by the NDV_(vec)H7N9,highlighting a potential benefit of engaging the complement system in H7N9 vaccine design.

关 键 词：H7N9 subtype avian influenza virus NDV vector vaccine antibody immunity COMPLEMENT protection 

分 类 号：S852.4[农业科学—基础兽医学]