title: Dendritic cells produce IL-12 and direct the development of Th1 cells from naive CD4+ T cells.
abstract: Dendritic cells are APCs that are unique in their potency to stimulate proliferation of primary Ag-specific responses in vitro and in vivo. In this study, we demonstrate that dendritic cells can produce IL-12, a dominant cytokine involved in the development of IFN-gamma-producing T cells. This finding resulted from our observations that dendritic cell-induced Th1 development from total CD4+ T cells upon neutralization of endogenous levels of IL-4 was IL-12-dependent. Furthermore, we demonstrate that dendritic cells can induce the development of Th1 cells from Ag-specific naive LECAM-1bright CD4+ T cells obtained from alpha beta-TCR transgenic mice, provided that CD4+ LECAM-1dull T cells, which produce significant levels of IL-4, are not present in the primary cultures. Production of IL-12 by dendritic cells was confirmed by positive immunofluoresence staining with Abs specific for the inducible IL-12 p40 subunit. This suggests that in addition to inducing proliferation and clonal expansion of naive T cells, dendritic cells, by their production of IL-12, play a direct role in the development of IFN-gamma-producing cells that are important for cell-mediated immune responses.
authors.affiliation: Department of Immunology, DNAX Research Institute of Molecular and Cellular Biology Inc., Palo Alto, CA 94303, USA.
authors.forename: S E
authors.initials: SE
authors.lastname: Macatonia
authors.forename: N A
authors.initials: NA
authors.lastname: Hosken
authors.forename: M
authors.initials: M
authors.lastname: Litton
authors.forename: P
authors.initials: P
authors.lastname: Vieira
authors.forename: C S
authors.initials: CS
authors.lastname: Hsieh
authors.forename: J A
authors.initials: JA
authors.lastname: Culpepper
authors.forename: M
authors.initials: M
authors.lastname: Wysocka
authors.forename: G
authors.initials: G
authors.lastname: Trinchieri
authors.forename: K M
authors.initials: KM
authors.lastname: Murphy
authors.forename: A
authors.initials: A
authors.lastname: O'Garra
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002454:Cell Differentiation / Q000276:immunology*; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000276:immunology*; D005260:Female; D005455:Fluorescent Antibody Technique; D018664:Interleukin-12 / Q000096:biosynthesis* / Q000276:immunology; D015847:Interleukin-4 / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008822:Mice, Transgenic; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics; D018417:Th1 Cells / Q000276:immunology*
chemical_list: D016693:Receptors, Antigen, T-Cell, alpha-beta; D018664:Interleukin-12; D015847:Interleukin-4