[Role of nitric oxide produced by activated macrophages in their cytocidal activity against glial tumor cells].
This study investigated the role of activated macrophages (M phi) in nitric oxide (NO) production and the tumoricidal effect of NO on glioma cells. Induced peritoneal M phi were prepared 6 days following the injection of thioglycollate broth into C3H/He N (H-2 kappa) mice. M phi were activated in vitro recombinant human interferon-gamma (IFN gamma) and lipopolysaccharide (LPS) into the culture medium of the elicited M phi. Two kinds of murine malignant glioma cell lines, RSV-M glioma (H-2 kappa) and VM-glioma (H-2b) were used as targets. P815 mastocytoma cells (H-2d) were used as a control target, since they are insensitive to tumor necrosis factor-alpha, but susceptible to NO derived from M phi. L-arginine-depleted medium was used to inhibit NO-mediated cytocidal activity against tumor cells. Cytotoxicity was assayed at various effector-to-target ratios using an admixture of M phi and 1.5 x 10(4) 125I-labeled target cells 48 hours following co-culture. NO was measured in culture medium using Griess reagent, and the concentration of NO was expressed as mu mol/ml NaNO2. Peritoneal M phi induced only 10% and 15% lysis of RSV-M glioma and VM glioma cells, respective, and LPS augmented this killing activity of M phi to a maximum of 1.2 to 1.4 fold in a dose-dependent manner with dosages from 1 to 50 ng/ml. LPS demonstrated a synergistic action on M phi-mediated cytotoxicity 4 hours following pretreatment with IFN gamma. Alternatively, low doses of IFN gamma alone had no enhancing effect on M phi tumoricidal activity.(ABSTRACT TRUNCATED AT 250 WORDS)
Akiyama
Y
Y
Department of Neurosurgery, Shimane Medical University, Japan.
Yamasaki
T
T
Fukuda
M
M
Moritake
K
K
D000818:Animals; D005910:Glioma / Q000276:immunology* / Q000473:pathology; D007371:Interferon-gamma / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008262:Macrophage Activation; D017737:Macrophages, Peritoneal / Q000378:metabolism*; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D009569:Nitric Oxide / Q000096:biosynthesis / Q000502:physiology*; D011994:Recombinant Proteins / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D008070:Lipopolysaccharides; D011994:Recombinant Proteins; D009569:Nitric Oxide; D007371:Interferon-gamma