title: Mice with asthma are more resistant to influenza virus infection and NK cells activated by the induction of asthma have potentially protective effects.
abstract: OBJECTIVE
  This study was conducted in order to investigate whether the virulence of the influenza virus infection is affected by asthma in mice.
  
  
  METHODS
  Mice with asthma or control mice were infected with influenza virus. The survival rate, body weight, virus titer, cytokine profile, and cell infiltration in bronchoalveolar lavage fluid (BALF) were measured. The NK cell cytotoxicity was determined by a co-culture system with YAC-1 cells, and the effects of NK cells were observed by depletion of NK cells using anti-asialoGM1 serum. The virus-specific CD8(+) T cell killing assay was also performed.
  
  
  RESULTS
  When asthmatic or control mice were infected with non- and sub-lethal doses of influenza virus, the asthmatic mice were more resistant to the virus than control mice with regard to the survival rate, the remission of body weight loss, and the virus burden. Anti-viral cytokines and the NK cell number were increased in the BALF of asthmatic mice before the infection. The NK cell cytotoxicity in the asthmatic mice was significantly enhanced compared to that in control mice, and the depletion of NK cells in asthmatic mice was abrogated both the improved survival rate and the recovery of the body weight loss. The antigen-specific CD8(+) T cell killing activity in asthmatic mice was also significantly increased following the infection compared to that in control mice.
  
  
  CONCLUSIONS
  NK cell activated by the induction of asthma and the subsequently activated antigen-specific CD8(+) T cells could promptly eliminate the viral-infected cells, thus leading to improvements in the morbidity and mortality of influenza virus infection.
authors: Department of Microbiology, Tokyo Medical University, 6-1-1 Shinjuku, Shinjuku-ku, Tokyo 160-8402, Japan. hiroki01@tokyo-med.ac.jp
authors: Hiroki
authors: H
authors: Ishikawa
authors: Hiraku
authors: H
authors: Sasaki
authors: Toshie
authors: T
authors: Fukui
authors: Koji
authors: K
authors: Fujita
authors: Etsuko
authors: E
authors: Kutsukake
authors: Tetsuya
authors: T
authors: Matsumoto
mesh_terms: D000818:Animals; D000918:Antibody Specificity; D001249:Asthma / Q000150:complications* / Q000276:immunology* / Q000401:mortality; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002465:Cell Movement / Q000276:immunology; D016207:Cytokines / Q000096:biosynthesis; D003602:Cytotoxicity, Immunologic; D004198:Disease Susceptibility / Q000276:immunology; D005260:Female; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D007371:Interferon-gamma / Q000096:biosynthesis; D007694:Killer Cells, Natural / Q000276:immunology*; D008168:Lung / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009976:Orthomyxoviridae Infections / Q000150:complications* / Q000276:immunology* / Q000517:prevention & control; D013154:Spleen / Q000276:immunology
chemical_list: D016207:Cytokines; D007073:Immunoglobulin E; D007371:Interferon-gamma