title: CD40/CD40 ligand interactions are required for T cell-dependent production of interleukin-12 by mouse macrophages.
abstract: We have previously shown that T cell receptor-activated mouse T helper (Th)1 clones induce the production of interleukin (IL)-12 by splenic antigen-presenting cells (APC). Here, we show that the expression of CD40L by activated T cells is critical for T cell-dependent IL-12 production by mouse macrophages. IL-12 was produced in cultures containing alloreactive Th1 clones stimulated with allogeneic peritoneal macrophages, or in cultures of splenocytes stimulated with anti-CD3. Anti-CD40L monoclonal antibodies (mAb) inhibited the production of IL-12, but not IL-2, in these cultures by approximately 90% and had dramatic inhibitory effects on antigen-dependent proliferation of Th1 clones. In addition, both activated T cells and a Th1 clone derived from CD40L knockout mice failed to induce IL-12 production from splenic APC or peritoneal macrophages. Finally, macrophages cultured in the absence of T cells produced IL-12 upon stimulation with soluble recombinant CD40L in combination with either supernatants from activated Th1 clones or with interferon-gamma and granulocyte/macrophage colony-stimulating factor. Thus, both CD40L-dependent and cytokine-mediated signals from activated T cells are required to induce the production of IL-12 by macrophages. A blockade at the level of IL-12 production may explain, at least in part, the dramatic ability of anti-CD40L mAb to inhibit disease in animal models that are dependent upon the generation of a cell-mediated immune response. Moreover, a defect in T cell-dependent induction of IL-12 may contribute to the immune status of humans that lack functional CD40L.
authors.affiliation: Immunex Corporation, Seattle, USA.
authors.forename: M K
authors.initials: MK
authors.lastname: Kennedy
authors.forename: K S
authors.initials: KS
authors.lastname: Picha
authors.forename: W C
authors.initials: WC
authors.lastname: Fanslow
authors.forename: K H
authors.initials: KH
authors.lastname: Grabstein
authors.forename: M R
authors.initials: MR
authors.lastname: Alderson
authors.forename: K N
authors.initials: KN
authors.lastname: Clifford
authors.forename: W A
authors.initials: WA
authors.lastname: Chin
authors.forename: K M
authors.initials: KM
authors.lastname: Mohler
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D019013:CD40 Antigens / Q000494:pharmacology*; D023201:CD40 Ligand; D002474:Cell-Free System / Q000276:immunology; D002999:Clone Cells; D016207:Cytokines / Q000494:pharmacology; D004347:Drug Interactions / Q000276:immunology; D005260:Female; D018664:Interleukin-12 / Q000096:biosynthesis*; D008213:Lymphocyte Activation; D017737:Macrophages, Peritoneal / Q000378:metabolism*; D008297:Male; D008562:Membrane Glycoproteins / Q000172:deficiency / Q000276:immunology / Q000494:pharmacology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D018345:Mice, Knockout; D011994:Recombinant Proteins / Q000494:pharmacology; D013601:T-Lymphocytes / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D019013:CD40 Antigens; D016207:Cytokines; D008562:Membrane Glycoproteins; D011994:Recombinant Proteins; D023201:CD40 Ligand; D018664:Interleukin-12