Comparative studies on the roles of mediator molecules in expression of the suppressor activity of Mycobacterium avium complex-induced immunosuppressive macrophages against T cell and B cell mitogenic responses.
Mycobacterium avium complex-induced immunosuppressive macrophages (MAC-MPhis) exhibit suppressor activity against concanavalin A-induced T cell mitogenesis (T cell Con A mitogenesis). We examined the profiles of the MAC-MPhi-mediated suppression of lipopolysaccharide-induced B cell mitogenesis (B cell LPS mitogenesis) and found the following. First, although N(G)-monomethyl-L-arginine and carboxy-PTIO effectively blocked the MAC-MPhi's suppressor activity against T cell Con A mitogenesis, MAC-MPhi's action against B cell LPS mitogenesis was only weakly affected by these NO-reducing agents. Second, B cell LPS mitogenesis was remarkably more susceptible to MAC-MPhi-derived reactive oxygen intermediates than T cell Con A mitogenesis. Third, B cell LPS mitogenesis was less susceptible to the inhibitory effects of the other MAC-MPhi-derived suppressor mediators, including free fatty acids, TGF-beta and prostaglandin E(2), than T cell Con A mitogenesis. Fourth, MAC-MPhi's suppressor activity was strongly dependent on B7-1 like molecule-mediated cell contact with target cells only in the case of T cell Con A mitogenesis. Therefore, there are significant differences in the modes of suppressor action of MAC-MPhis against T cell and B cell mitogenesis.
Department of Microbiology and Immunology, Shimane University School of Medicine, Izumo, Shimane 693-8501, Japan.
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Cai
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Shimizu
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Tomioka
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D002450:Cell Communication / Q000276:immunology; D002478:Cells, Cultured; D003208:Concanavalin A / Q000276:immunology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007108:Immune Tolerance; D007111:Immunity, Cellular; D008213:Lymphocyte Activation / Q000276:immunology; D008264:Macrophages / Q000276:immunology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D015269:Mycobacterium avium Complex / Q000276:immunology; D015270:Mycobacterium avium-intracellulare Infection / Q000276:immunology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D017382:Reactive Oxygen Species / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D019323:omega-N-Methylarginine / Q000276:immunology
D004791:Enzyme Inhibitors; D017382:Reactive Oxygen Species; D003208:Concanavalin A; D019323:omega-N-Methylarginine; D019001:Nitric Oxide Synthase