title: IL-18 bridges innate and adaptive immunity through IFN-gamma and the CD134 pathway.
abstract: IL-18 induces inflammation resulting in either enhanced protection from pathogens or exacerbation of autoimmunity, and T cells are profoundly activated during these responses. How IL-18 influences T cell activation is unknown, but this study in mice shows that IL-18 boosted Ag-specific T cell clonal expansion of effector T cells and induced a subpopulation of IFN-gamma superproducing T cells. Commitment to IFN-gamma production through IL-18 was independent of NK cells and IL-12 but dependent on host-derived IFN-gamma. To determine how expansion of these effectors occurred, IL-18 was shown to induce OX40L on dendritic cells, whereas peptide stimulation induced CD134 (OX40) on specific T cells. CD134 blockade inhibited T cell effector expansion thereby reducing the number of IFN-gamma superproducers by 12-fold. Thus, independent of IL-12, IL-18 impacts T cell immunity throughout lymphoid and nonlymphoid tissue by bridging the innate and adaptive arms of the immune system through IFN-gamma and the CD134 costimulatory pathway.
authors.affiliation: Department of Immunology, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030, USA.
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Maxwell
authors.forename: Rajwardhan
authors.initials: R
authors.lastname: Yadav
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Rossi
authors.forename: Carl E
authors.initials: CE
authors.lastname: Ruby
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Weinberg
authors.forename: Hector L
authors.initials: HL
authors.lastname: Aguila
authors.forename: Anthony T
authors.initials: AT
authors.lastname: Vella
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage / Q000502:physiology*; D019264:Adoptive Transfer; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D002478:Cells, Cultured; D018984:Epitopes, T-Lymphocyte / Q000008:administration & dosage / Q000276:immunology; D007111:Immunity, Cellular / Q000235:genetics; D007113:Immunity, Innate / Q000235:genetics; D007371:Interferon-gamma / Q000096:biosynthesis / Q000502:physiology*; D018664:Interleukin-12 / Q000502:physiology; D020382:Interleukin-18 / Q000008:administration & dosage / Q000502:physiology*; D053727:Interleukin-18 Receptor alpha Subunit; D007694:Killer Cells, Natural / Q000276:immunology; D008198:Lymph Nodes / Q000166:cytology / Q000276:immunology / Q000637:transplantation; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D018123:Receptors, Interleukin / Q000172:deficiency / Q000235:genetics; D053724:Receptors, Interleukin-18; D053262:Receptors, OX40; D018124:Receptors, Tumor Necrosis Factor / Q000037:antagonists & inhibitors / Q000276:immunology / Q000502:physiology*; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology*; D013154:Spleen / Q000166:cytology / Q000276:immunology / Q000637:transplantation
chemical_list: D000276:Adjuvants, Immunologic; D018984:Epitopes, T-Lymphocyte; C508573:Il18r1 protein, mouse; D020382:Interleukin-18; D053727:Interleukin-18 Receptor alpha Subunit; D018123:Receptors, Interleukin; D053724:Receptors, Interleukin-18; D053262:Receptors, OX40; D018124:Receptors, Tumor Necrosis Factor; C505717:Tnfrsf4 protein, mouse; D018664:Interleukin-12; D007371:Interferon-gamma