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Macrophage-produced oxygen radical generating activities for polymorphonuclear leukocytes
Y Tsukamoto1, S Fukutani, M Nakatani
1Department of Pharmacology, Osaka Dental University, Japan.
Inflammation
|June 1, 1989
Summary
Bacterial lipopolysaccharide stimulation of guinea pig macrophages releases factors that enhance superoxide (O2-) production in other immune cells. These factors appear quickly and are sensitive to heat and enzymes.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Macrophages are key immune cells involved in host defense.
- Bacterial lipopolysaccharide (LPS) is a potent activator of macrophages.
- Superoxide (O2-) production is a critical function of phagocytic immune cells.
Purpose of the Study:
- To investigate the effect of LPS-stimulated guinea pig macrophages on polymorphonuclear leukocyte (PMN) O2- production.
- To characterize the nature of the factors released by macrophages.
Main Methods:
- Guinea pig peritoneal macrophages were stimulated in vitro with LPS.
- Supernatants from macrophage cultures were collected.
- Supernatants were tested for their ability to induce O2- production in guinea pig peritoneal PMNs.
- Sensitivity of the activity to heat and trypsin was assessed.
- Effect of cycloheximide on activity production was evaluated.
Main Results:
- LPS-stimulated macrophage supernatants significantly increased O2- generating activity in PMNs.
- This activity appeared within 2 hours of LPS stimulation.
- Supernatants from non-stimulated macrophages did not induce this activity.
- The activity was abolished by heating or trypsin treatment.
- Cycloheximide inhibited the production of these activities.
Conclusions:
- LPS-stimulated macrophages release soluble factors that enhance PMN superoxide production.
- These factors are likely proteins, as they are sensitive to heat and trypsin.
- Their production is dependent on de novo protein synthesis by macrophages.