Macrophage-stimulating protein inhibits induction of nitric oxide production by endotoxin- or cytokine-stimulated mouse macrophages.
Human serum macrophage-stimulating protein (MSP) is a disulfide-linked heterodimer that induces motile and phagocytic activity of mouse resident peritoneal macrophages. In this work, we found that MSP blocked the increase in macrophage nitric oxide synthase mRNA, as well as the associated increase in nitric oxide production, that occurred in response to several stimuli. These included bacterial products and mammalian cytokines: endotoxin, and interferon-gamma plus endotoxin, interleukin-2, or tumor necrosis factor-alpha. The inhibition by MSP of induction of nitric oxide synthase mRNA and nitric oxide secretion was concentration-dependent. The concentration of MSP that caused maximal inhibition of nitric oxide production was comparable with the optimum for stimulation of macrophage motile and phagocytic activity. Time course studies showed that nitrite was first detected in culture fluid about 8 h after endotoxin stimulation, and it accumulated at a linear rate during the ensuing 16 h. Inhibition by MSP occurred during the 8-h lipopolysaccharide (LPS) induction period; inhibition was maximal when MSP and LPS were added together and decreased progressively to no inhibition as the interval between LPS and MSP addition increased to 11 h.
Wang
M H
MH
Laboratory of Immunobiology, National Cancer Institute-Frederick Cancer Research and Development Center, Maryland 21702-1201.
Cox
G W
GW
Yoshimura
T
T
Sheffler
L A
LA
Skeel
A
A
Leonard
E J
EJ
D000594:Amino Acid Oxidoreductases / Q000235:genetics; D000818:Animals; D016207:Cytokines / Q000502:physiology; D004731:Endotoxins / Q000502:physiology; D006133:Growth Substances / Q000502:physiology*; D017228:Hepatocyte Growth Factor; D006801:Humans; D007700:Kinetics; D008262:Macrophage Activation; D017737:Macrophages, Peritoneal / Q000378:metabolism*; D051379:Mice; D008809:Mice, Inbred C3H; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger / Q000096:biosynthesis
D016207:Cytokines; D004731:Endotoxins; D006133:Growth Substances; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; C082332:macrophage stimulating protein; D009569:Nitric Oxide; D017228:Hepatocyte Growth Factor; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases