The programmed death-1 (PD-1) costimulatory receptor inhibits T and B cell responses and plays a crucial role in peripheral tolerance. PD-1 has recently been shown to inhibit T cell responses during chronic viral infections such as HIV. In this study, we examined the role of PD-1 in infection with Mycobacterium tuberculosis, a common co-infection with HIV. PD-1-deficient mice showed dramatically reduced survival compared with wild-type mice. The lungs of the PD-1-/- mice showed uncontrolled bacterial proliferation and focal necrotic areas with predominantly neutrophilic infiltrates, but a lower number of infiltrating T and B cells. Proinflammatory cytokines, such as TNF-α, IL-1, and especially IL-6 and IL-17 were significantly increased in the lung and sera of infected PD-1-/- mice, consistent with an aberrant inflammation. Microarray analysis of the lungs infected with M. tuberculosis showed dramatic differences between PD-1-/- and control mice. Using high-stringency analysis criteria (changes of twofold or greater), 367 transcripts of genes were differentially expressed between infected PD-1 -/- and wild-type mice, resulting in profoundly altered inflammatory responses with implications for both innate and adaptive immunity. Overall, our studies show that the PD-1 pathway is required to control excessive inflammatory responses after M. tuberculosis infection in the lungs.
|Original language||English (US)|
|Number of pages||6|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - Jul 27 2010|
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