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Inhibition of Pulmonary Anti‐Bacterial Defense by IFN‐γ Induced During Influenza Virus Infection
Author(s) -
Sun Keer,
Metzger Dennis W.
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.857.7
Subject(s) - immunology , lung , virus , microbiology and biotechnology , phagocytosis , innate immune system , influenza a virus , immunity , biology , virology , immune system , medicine
Secondary bacterial infection often follows pulmonary virus infection and is a common cause of severe disease in humans, yet the mechanisms responsible for this viral‐bacterial synergy in the lung are only poorly understood. We found that pulmonary IFN‐γ produced during T cell responses to influenza infection inhibited initial bacterial clearance from the lung by alveolar macrophages. This suppression of phagocytosis then led to enhanced susceptibility to secondary pneumococcal infection, which could be prevented by IFN‐γ neutralization following influenza infection. Inoculation of exogenous IFN‐γ i.n. to naive mice mimicked viral infection and led to decreased bacterial killing. Thus, IFN‐γ, while likely facilitating induction of specific anti‐influenza immunity, suppresses innate protection against extracellular bacterial pathogens in the lung. (Supported by NIH grant RO1 AI 41715)