Tpl2 kinase regulates T cell interferon-{gamma} production and host resistance

J Exp Med. 2008 Nov 10. [Epub ahead of print]

Tpl2 kinase regulates T cell interferon-{gamma} production and host resistance to Toxoplasma gondii

Watford WT, Hissong BD, Durant LR, Yamane H, Muul LM, Kanno Y, Tato CM, Ramos HL, Berger AE, Mielke L, Pesu M, Solomon B, Frucht DM, Paul WE, Sher A, Jankovic D, Tsichlis PN, O'Shea JJ.

Lymphocyte Cell Biology Section, Molecular Immunology and Inflammation Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892.

Tpl2 (Tumor progression locus 2), also known as Cot/MAP3K8, is a hematopoietically expressed serine-threonine kinase. Tpl2 is known to have critical functions in innate immunity in regulating tumor necrosis factor-alpha, Toll-like receptor, and G protein-coupled receptor signaling; however, our understanding of its physiological role in T cells is limited. We investigated the potential roles of Tpl2 in T cells and found that it was induced by interleukin-12 in human and mouse T cells in a Stat4-dependent manner. Deficiency of Tpl2 was associated with impaired interferon (IFN)-gamma production. Accordingly, Tpl2(-/-) mice had impaired host defense against Toxoplasma gondii with reduced parasite clearance and decreased IFN-gamma production. Furthermore, reconstitution of Rag2(-/-) mice with Tpl2-deficient T cells followed by T. gondii infection recapitulated the IFN-gamma defect seen in the Tpl2-deficient mice, confirming a T cell-intrinsic defect. CD4(+) T cells isolated from Tpl2(-/-) mice showed poor induction of T-bet and failure to up-regulate Stat4 protein, which is associated with impaired TCR-dependent extracellular signal-regulated kinase activation. These data underscore the role of Tpl2 as a regulator of T helper cell lineage decisions and demonstrate that Tpl2 has an important functional role in the regulation of Th1 responses.

PMID: 19001140 [PubMed - as supplied by publisher]