title: Macrophage synthesis of nitric oxide in the mouse mixed leucocyte reaction.
abstract: The production of nitric oxide (.N = O) in the splenocyte mixed leucocyte reaction (MLR) results in inhibition of allospecific lymphocyte effector function. In order to more clearly define the circumstances which promote .N = O synthesis in the MLR, responder accessory cell depleted spleen cells (ACDSC) were co-cultured with allogeneic macrophage cell lines or peritoneal macrophages. .N = O synthesis and C57BL/6 (H-2b) ACDSC proliferation were concurrently monitored in cultures comparing RAW 264.7 (H-2d, a high .N = O producer), P388D1 (H-2d, a low .N = O and BALB/c (H-2d) peritoneal macrophages as allogeneic antigen presenting cells (APC). A concentration-dependent increase in lymphocyte proliferation was observed in the presence of 1 x 10(4) to 1 x 10(5) P388D1. In contrast, addition of NG-monomethyl-L-arginine (NMA), a competitive inhibitor of .N = O synthase, was necessary in order to observe lymphocyte proliferation in the presence of increasing numbers of RAW 264.7 and BALB/c peritoneal macrophages. The addition of both anti-IL-2 and anti-IFN gamma (interferon-gamma) monoclonal antibodies inhibited .N = O synthesis in alloantigen-stimulated cultures. The IFN gamma induced expression of class II antigen, as well as the constitutive expression of class I antigen, on RAW 264.7 was similar in the presence or absence of NMA, indicating that induction of .N = O synthesis by IFN gamma does not inhibit H-2 antigen expression. Thus, cytokines produced as a result of alloimmune interaction initiate macrophage .N = O synthesis. However, allogeneic APC function, as assessed by H-2 antigen expression and subsequent stimulatory capacity of MLR, is not affected by initiation of the .N = O pathway.
authors.affiliation: Department of Surgery, University of Pittsburgh, PA 15213.
authors.forename: R A
authors.initials: RA
authors.lastname: Hoffman
authors.forename: J M
authors.initials: JM
authors.lastname: Langrehr
authors.forename: K E
authors.initials: KE
authors.lastname: Dull
authors.forename: S A
authors.initials: SA
authors.lastname: McCarthy
authors.forename: M L
authors.initials: ML
authors.lastname: Jordan
authors.forename: R L
authors.initials: RL
authors.lastname: Simmons
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000938:Antigen-Presenting Cells / Q000502:physiology; D002460:Cell Line; D005260:Female; D015395:Histocompatibility Antigens Class I / Q000032:analysis; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D007371:Interferon-gamma / Q000494:pharmacology; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D009569:Nitric Oxide / Q000096:biosynthesis*
chemical_list: D000911:Antibodies, Monoclonal; D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; D009569:Nitric Oxide; D007371:Interferon-gamma