During influenza A virus (IAV) infection, changes in the lung’s physical and immunological defenses predispose the host to bacterial superinfections. Invariant natural killer T (iNKT) cells are innate-like T lymphocytes that have beneficial or harmful functions during infection. We investigated the iNKT cells’ role in a model of invasive pneumococcal superinfection. The use of Jα18^{-/-} mice indicated that iNKT cells limited susceptibility to influenza-pneumococcal infection and reduced the lethal synergism. This role did not depend on immune-based anti-bacterial mechanisms. At the time of bacterial exposure, iNKT cells from IAV-experienced mice failed to produce antipneumococcal interferon-γ and adoptive transfer of fresh iNKT cells before Streptococcus pneumoniae challenge did not restore anti-bacterial host defenses. Impaired iNKT cell activation in superinfected animals was related to the IAV-induced immunosuppressive cytokine interleukin-10 (IL-10), rather than to an intrinsic functional defect. IL-10 dampened the activation of iNKT cells in response to pneumococci by inhibiting the production of IL-12 by pulmonary monocyte-derived dendritic cells. Neutralization of IL-10 restored iNKT cell activation and tends to increase resistance to secondary bacterial infection. Overall, iNKT cells have a beneficial role (upstream of bacterial colonization) in controlling influenza-pneumococcal superinfection, although they represent novel targets of immunosuppression at the time of bacterial challenge.
Influenza A virus-induced release of interleukin-10 inhibits the anti-microbial activities of invariant natural killer T cells during invasive pneumococcal superinfection
인플루엔자 A 바이러스에 의해 유도된 인터루킨-10의 방출은 침습성 폐렴구균 중복 감염 동안 불변 자연 살해 T 세포의 항미생물 활성을 억제한다.
[Category] 폐렴구균 감염증,
[Article Type] journal-article
[Source] pubmed
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