title: Pathogenesis and immunogenicity of an avian H9N2 influenza virus isolated from human.
abstract: OBJECTIVE
  To investigate the pathogenesis and immunogenicity of H9N2 influenza virus A/Guangzhou/333/99 (a reassortant of G1 and G9 viruses isolated from a female patient in 1999) in a mouse model of infection.
  
  
  METHODS
  Mice were infected with increasing virus titers. Viral load in the lungs and trachea was determined by EID50 assay. Pulmonary histopathology was assessed by hematoxylin-eosin staining. Anti-HI antibody titers and T-cell responses to viral HA were determined by ELISPOT and confirmed by flow cytometry.
  
  
  RESULTS
  Mice presented a mild syndrome after intranasal infection with A/Guangzhou/333/99 (H9N2) influenza virus. Virus was detected in the trachea and lungs of mice harvested on days 3, 6, and 9 post-infection. A T-cell response to viral HA was detected on day 6 and H9 HA-specific CD(4+) T-cells predominated. Seroconversion was detected after 14 days and antibody persisted for at least 28 weeks.
  
  
  CONCLUSIONS
  Our results suggest that H9N2 (A/Guangzhou/333/99) can replicate in the murine respiratory tract without prior adaptation, and both humoral and cell-mediated immunity play an important role in the immune response.
authors: State Key Laboratory for Molecular Virology and Genetic Engineering, Chinese National Influenza Center, National Institute for Viral Disease Control and Prevention, China CDC, Beijing 102206, China.
authors: LiQi
authors: L
authors: Liu
authors: Li
authors: L
authors: Zi
authors: JianFang
authors: J
authors: Zhou
authors: Yun
authors: Y
authors: Zhu
authors: Jie
authors: J
authors: Dong
authors: Xiang
authors: X
authors: Zhao
authors: JunFeng
authors: J
authors: Guo
authors: YueLong
authors: Y
authors: Shu
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002460:Cell Line; D004285:Dogs; D058501:Enzyme-Linked Immunospot Assay; D005260:Female; D006385:Hemagglutination Inhibition Tests; D006389:Hemagglutinins, Viral / Q000276:immunology; D006801:Humans; D007223:Infant; D053127:Influenza A Virus, H9N2 Subtype / Q000276:immunology / Q000302:isolation & purification / Q000472:pathogenicity*; D007371:Interferon-gamma / Q000276:immunology; D008168:Lung / Q000821:virology; D008214:Lymphocytes / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D009976:Orthomyxoviridae Infections / Q000276:immunology / Q000821:virology*; D013154:Spleen / Q000276:immunology; D014132:Trachea / Q000821:virology; D019562:Viral Load; D014774:Virulence
chemical_list: D006389:Hemagglutinins, Viral; D007371:Interferon-gamma