title: Influenza virus directly infects human natural killer cells and induces cell apoptosis.
abstract: Influenza is an acute respiratory viral disease that is transmitted in the first few days of infection. Evasion of host innate immune defenses, including natural killer (NK) cells, is important for the virus's success as a pathogen of humans and other animals. NK cells encounter influenza viruses within the microenvironment of infected cells and are important for host innate immunity during influenza virus infection. It is therefore important to investigate the direct effects of influenza virus on NK cells. In this study, we demonstrated for the first time that influenza virus directly infects and replicates in primary human NK cells. Viral entry into NK cells was mediated by both clathrin- and caveolin-dependent endocytosis rather than through macropinocytosis and was dependent on the sialic acids on cell surfaces. In addition, influenza virus infection induced a marked apoptosis of NK cells. Our findings suggest that influenza virus can directly target and kill NK cells, a potential novel strategy of influenza virus to evade the NK cell innate immune defense that is likely to facilitate viral transmission and may also contribute to virus pathogenesis.
authors: Department of Paediatrics & Adolescent Medicine, the University of Hong Kong, Hong Kong SAR, People's Republic of China.
authors: Huawei
authors: H
authors: Mao
authors: Wenwei
authors: W
authors: Tu
authors: Gang
authors: G
authors: Qin
authors: Helen Ka Wai
authors: HK
authors: Law
authors: Sin Fun
authors: SF
authors: Sia
authors: Ping-Lung
authors: PL
authors: Chan
authors: Yinping
authors: Y
authors: Liu
authors: Kwok-Tai
authors: KT
authors: Lam
authors: Jian
authors: J
authors: Zheng
authors: Malik
authors: M
authors: Peiris
authors: Yu-Lung
authors: YL
authors: Lau
mesh_terms: D017209:Apoptosis; D022461:Caveolins; D002966:Clathrin; D004705:Endocytosis; D006801:Humans; D007113:Immunity, Innate; D007694:Killer Cells, Natural / Q000821:virology*; D009975:Orthomyxoviridae / Q000276:immunology / Q000472:pathogenicity*; D012794:Sialic Acids; D053586:Virus Internalization
chemical_list: D022461:Caveolins; D002966:Clathrin; D012794:Sialic Acids