title: Efficient replication and strong induction of innate immune responses by H9N2 avian influenza virus in human dendritic cells.
abstract: Avian influenza A (H9N2) viruses have occasionally been identified in humans with upper respiratory tract infections. The novel H7N9/2013 virus identified in China shows that a low pathogenic avian influenza (LPAI) virus can be highly pathogenic in humans. Therefore, it is important to understand virus-host cell interactions and immune responses triggered by LPAI viruses in humans. We found that LPAI A/Hong Kong/1073/99 (H9N2) virus replicated efficiently in human dendritic cells (DCs). The H9N2 virus induced strong IFN gene expression although with different kinetics than seasonal influenza A/Beijing/353/89 (H3N2) virus. IFN inducible antiviral proteins were produced in H9N2 virus-infected cells at the same level as in H3N2 infection. The H9N2 virus was extremely sensitive to the antiviral actions of type I IFNs. These results indicate that the avian influenza H9N2 virus is inducing a strong antiviral IFN response in human DCs.
authors.affiliation: Virology Unit, National Institute for Health and Welfare (THL), Mannerheimintie 166, FI-00271 Helsinki, Finland. Electronic address: veera.westenius@thl.fi.
authors.forename: Veera
authors.initials: V
authors.lastname: Westenius
authors.affiliation: Virology Unit, National Institute for Health and Welfare (THL), Mannerheimintie 166, FI-00271 Helsinki, Finland.
authors.forename: Sanna M
authors.initials: SM
authors.lastname: Mäkelä
authors.affiliation: Virology Unit, National Institute for Health and Welfare (THL), Mannerheimintie 166, FI-00271 Helsinki, Finland; Research Center for Child Psychiatry, University of Turku, Lemminkäisenkatu 3, 20014 Turku, Finland.
authors.forename: Thedi
authors.initials: T
authors.lastname: Ziegler
authors.affiliation: Virology Unit, National Institute for Health and Welfare (THL), Mannerheimintie 166, FI-00271 Helsinki, Finland; Department of Virology, University of Turku, Kiinamyllynkatu 13, 20520 Turku, Finland.
authors.forename: Ilkka
authors.initials: I
authors.lastname: Julkunen
authors.affiliation: Virology Unit, National Institute for Health and Welfare (THL), Mannerheimintie 166, FI-00271 Helsinki, Finland.
authors.forename: Pamela
authors.initials: P
authors.lastname: Österlund
mesh_terms: D015153:Blotting, Western; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000821:virology*; D004797:Enzyme-Linked Immunosorbent Assay; D015967:Gene Expression Regulation, Viral / Q000276:immunology; D006801:Humans; D007113:Immunity, Innate; D053127:Influenza A Virus, H9N2 Subtype / Q000502:physiology*; D007372:Interferons / Q000235:genetics / Q000378:metabolism; D014776:Virus Cultivation; D014779:Virus Replication / Q000502:physiology*
chemical_list: D007372:Interferons
keywords: Avian influenza; Cytokine; Gene expression; H9N2 virus; IFNs; Innate immunity