title: IL-12 and type-I IFN synergize for IFN-gamma production by CD4 T cells, whereas neither are required for IFN-gamma production by CD8 T cells after Listeria monocytogenes infection.
abstract: Differentiation of Ag-specific T cells into IFN-gamma producers is essential for protective immunity to intracellular pathogens. In addition to stimulation through the TCR and costimulatory molecules, IFN-gamma production is thought to require other inflammatory cytokines. Two such inflammatory cytokines are IL-12 and type I IFN (IFN-I); both can play a role in priming naive T cells to produce IFN-gamma in vitro. However, their role in priming Ag-specific T cells for IFN-gamma production during experimental infection in vivo is less clear. In this study, we examine the requirements for IL-12 and IFN-I, either individually or in combination, for priming Ag-specific T cell IFN-gamma production after Listeria monocytogenes (Lm) infection. Surprisingly, neither individual nor combined defects in IL-12 or IFN-I signaling altered IFN-gamma production by Ag-specific CD8 T cells after Lm infection. In contrast, individual defects in either IL-12 or IFN-I signaling conferred partial ( approximately 50%) reductions, whereas combined deficiency in both IL-12 and IFN-I signaling conferred more dramatic (75-95%) reductions in IFN-gamma production by Ag-specific CD4 T cells. The additive effects of IL-12 and IFN-I signaling on IFN-gamma production by CD4 T cells were further demonstrated by adoptive transfer of transgenic IFN-IR(+/+) and IFN-IR(-/-) CD4 T cells into normal and IL-12-deficient mice, and infection with rLm. These results demonstrate an important dichotomy between the signals required for priming IFN-gamma production by CD4 and CD8 T cells in response to bacterial infection.
authors: Department of Pediatrics, University of Washington School of Medicine, 1959 Northeast Pacific Street, Seattle, WA 98195, USA. singsing@u.washington.edu
authors: Sing Sing
authors: SS
authors: Way
authors: Colin
authors: C
authors: Havenar-Daughton
authors: Ganesh A
authors: GA
authors: Kolumam
authors: Nural N
authors: NN
authors: Orgun
authors: Kaja
authors: K
authors: Murali-Krishna
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000637:transplantation; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D007370:Interferon Type I / Q000235:genetics / Q000502:physiology*; D007371:Interferon-gamma / Q000378:metabolism; D018664:Interleukin-12 / Q000235:genetics / Q000502:physiology*; D008089:Listeria monocytogenes; D008088:Listeriosis / Q000276:immunology*; D051379:Mice; D008817:Mice, Mutant Strains
chemical_list: D007370:Interferon Type I; D018664:Interleukin-12; D007371:Interferon-gamma