title: Differential effects of IL-12 on the generation of alloreactive CTL mediated by murine and human dendritic cells: a critical role for nitric oxide.
abstract: We examined the mechanisms involved in interleukin (IL)-12-mediated suppression of cellular immunity in mice using allogeneic mixed leukocyte reaction (MLR) stimulated by dendritic cells (DCs) in vitro and compared the effect of IL-12 on MLR in mice and humans. Although IL-12 stimulated human MLR, the addition of IL-12 or interferon-gamma (IFN-gamma) resulted in a dose-dependent suppression of MLR in mice. The treatment with N(G)-monomethyl-L-arginine (L-NMMA) completely abrogated IL-12- and IFN-gamma-mediated suppression of MLR in mice. Furthermore, IL-12 enhanced the alloreactive cytolytic T lymphocyte (CTL) induction in human MLR, whereas the addition of L-NMMA was required to generate alloreactive CTLs in the presence of IL-12 in mice. Nitric oxide (NO) was detected only in mouse MLR. Murine DCs could produce NO, but neither human CD34(+) cell- nor monocyte-derived DCs produced a detectable amount of NO. These results suggest that NO produced by DCs might play an important role in IL-12-mediated immune suppression in mice but not in humans.
authors.affiliation: Third Department of Internal Medicine, University of Tokushima School of Medicine, Japan. yasuhiko@clin.med.tokushima.u.ac-jp
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Nishioka
authors.forename: Hua
authors.initials: H
authors.lastname: Wen
authors.forename: Kayo
authors.initials: K
authors.lastname: Mitani
authors.forename: Paul D
authors.initials: PD
authors.lastname: Robbins
authors.forename: Michael T
authors.initials: MT
authors.lastname: Lotze
authors.forename: Saburo
authors.initials: S
authors.lastname: Sone
authors.forename: Hideaki
authors.initials: H
authors.lastname: Tahara
mesh_terms: D000818:Animals; D017951:Antigen Presentation; D001854:Bone Marrow Cells / Q000276:immunology / Q000378:metabolism; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism; D005260:Female; D006801:Humans; D007108:Immune Tolerance / Q000502:physiology; D007111:Immunity, Cellular / Q000187:drug effects; D007371:Interferon-gamma / Q000494:pharmacology; D018664:Interleukin-12 / Q000494:pharmacology*; D007959:Lymphocyte Culture Test, Mixed; D016399:Lymphoma, T-Cell / Q000473:pathology; D034801:Mastocytoma / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D009569:Nitric Oxide / Q000096:biosynthesis / Q000502:physiology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D026423:S-Nitroso-N-Acetylpenicillamine / Q000494:pharmacology; D013045:Species Specificity; D013602:T-Lymphocytes, Cytotoxic / Q000187:drug effects* / Q000276:immunology; D014407:Tumor Cells, Cultured; D019323:omega-N-Methylarginine / Q000494:pharmacology
chemical_list: D020030:Nitric Oxide Donors; D018664:Interleukin-12; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D026423:S-Nitroso-N-Acetylpenicillamine; D007371:Interferon-gamma