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Enhanced Tim3 activity improves survival after influenza infection
Journal article   Peer reviewed

Enhanced Tim3 activity improves survival after influenza infection

Josalyn L Cho, Marly I Roche, Barry Sandall, Abraham L Brass, Brian Seed, Ramnik J Xavier and Benjamin D Medoff
The Journal of immunology (1950), Vol.189(6), pp.2879-2889
09/15/2012
DOI: 10.4049/jimmunol.1102483
PMCID: PMC3436990
PMID: 22875804

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Abstract

Influenza is a major cause of morbidity and mortality in the United States. Studies have shown that excessive T cell activity can mediate pneumonitis in the setting of influenza infection, and data from the 2009 H1N1 pandemic indicate that critical illness and respiratory failure postinfection were associated with greater infiltration of the lungs with CD8+ T cells. T cell Ig and mucin domain 3 (Tim3) is a negative regulator of Th1/Tc1-type immune responses. Activation of Tim3 on effector T cells has been shown to downregulate proliferation, cell-mediated cytotoxicity, and IFN-γ production, as well as induce apoptosis. In this article, we demonstrate that deletion of the terminal cytoplasmic domain of the Tim3 gene potentiates its ability to downregulate Tc1 inflammation, and that this enhanced Tim3 activity is associated with decreased phosphorylation of the TCR-CD3ζ-chain. We then show that mice with this Tim3 mutation infected with influenza are protected from morbidity and mortality without impairment in viral clearance or functional heterotypic immunity. This protection is associated with decreased CD8+ T cell proliferation and decreased production of inflammatory cytokines, including IFN-γ. Furthermore, the Tim3 mutation was protective against mortality in a CD8+ T cell-specific model of pneumonitis. These data suggest that Tim3 could be targeted to prevent immunopathology during influenza infection and demonstrate a potentially novel signaling mechanism used by Tim3 to downregulate the Tc1 response.
CD8-Positive T-Lymphocytes - pathology Receptors, Virus - metabolism Receptors, Virus - genetics Orthomyxoviridae Infections - genetics Receptors, Virus - physiology Signal Transduction - immunology Phosphorylation - genetics CD8-Positive T-Lymphocytes - metabolism Phosphorylation - immunology Disease Models, Animal Cytotoxicity, Immunologic - genetics Sequence Deletion - immunology Mice, Inbred C57BL Mice, Transgenic Up-Regulation - genetics Signal Transduction - genetics CD3 Complex - metabolism Hepatitis A Virus Cellular Receptor 2 Down-Regulation - genetics Animals Orthomyxoviridae Infections - mortality Up-Regulation - immunology Down-Regulation - immunology Survival Analysis Mice CD8-Positive T-Lymphocytes - immunology Orthomyxoviridae Infections - immunology Sequence Deletion - genetics

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