title: MDHM, a macrophage-activating product of Mycoplasma fermentans, stimulates murine macrophages to synthesize nitric oxide and become tumoricidal.
abstract: In continuation of previous work on macrophage activation by a Mycoplasma fermentans-derived product, originally named "mycoplasma-derived high mol. wt. material" (MDHM), we have investigated whether MDHM was capable of inducing synthesis of the reactive nitrogen intermediate nitric oxide (NO), thus rendering macrophages cytocidal. Mycoplasmas were first delipidated with acetone, and MDHM activity was then extracted with 50 mM 1-O-octyl-beta-D-glucopyranoside to yield a particularly active new preparation of MDHM which we have named MDHM-D (D for detergent). In combination with IFN-gamma, MDHM-D activated macrophages to produce reactive nitrogen intermediates and kill P815 mastocytoma cells in co-culture. P815 target cells were chosen because they are TNF-resistant. Macrophages from the LPS-low responder strain C3H/HeJ were used to minimize interference from possible LPS contamination. MDHM-D activity in this system was strictly IFN-gamma-dependent. In the presence of 25 U/ml IFN-gamma MDHM-D gave a half maximal response at a dilution of 1/100,000, showing a parallel concentration dependency for nitrite production and cytocidal activity.
authors.affiliation: Immunology Research Group, Gesellschaft für Biotechnologische Forschung, Braunschweig, FRG.
authors.forename: D
authors.initials: D
authors.lastname: Ruschmeyer
authors.forename: H
authors.initials: H
authors.lastname: Thude
authors.forename: P F
authors.initials: PF
authors.lastname: Mühlradt
mesh_terms: D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D003602:Cytotoxicity, Immunologic; D005260:Female; D007371:Interferon-gamma / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008262:Macrophage Activation; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000276:immunology*; D012515:Mast-Cell Sarcoma; D051379:Mice; D008809:Mice, Inbred C3H; D016858:Mycoplasma fermentans / Q000276:immunology*; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D011994:Recombinant Proteins; D014407:Tumor Cells, Cultured; D019323:omega-N-Methylarginine
chemical_list: D008070:Lipopolysaccharides; D011994:Recombinant Proteins; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D007371:Interferon-gamma; D001120:Arginine