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Production of tumor necrosis factor alpha by resident and activated murine macrophages
K Tachibana1, G J Chen, D S Huang
1Department of Fishery Food Sciences, Faculty of Fisheries, Nagasaki University, Japan.
Abstract:
Alveolar macrophages (Am phi s), resident peritoneal macrophages (RPm phi s), and thioglycolate-elicited peritoneal macrophages (TGPm phi s) were isolated from C57BL/6 mice and incubated with lipopolysaccharide (LPS), stimulated cell supernatant, or recombinant interferon gamma (IFN-gamma) for 24 h. Tumor necrosis factor (TNF) in cell-free supernatants was measured by enzyme-linked immunosorbent assay. Amo phi s incubated with 10(3) ng/ml LPS produced 50 times more TNF than RPm phi s and 5 times more than TGPm phi s, and LPS alone induced maximum TNF production by Am phi s. Stimulated cell supernatant or recombinant IFN-gamma alone did not induce TNF production. A combination of LPS with stimulated cell supernatant or IFN-gamma had only a limited synergistic effect on TNF production by Am phi s. However, both LPS and stimulated cell supernatant or recombinant IFN-gamma induced maximum TNF production by RPm phi s and TGPm phi s. TGPm phi s showed greater sensitivity to LPS and stimulated cell supernatant or IFN-gamma with regard to TNF production than the other macrophage populations investigated.
Insights
Alveolar macrophages produce significantly more tumor necrosis factor (TNF) in response to lipopolysaccharide (LPS) than peritoneal macrophages. However, peritoneal macrophages require combined stimuli for maximum TNF production, unlike alveolar macrophages.
Area of Science:
- Immunology
- Cell Biology
Background:
- Macrophages are critical immune cells with diverse functions.
- Different macrophage populations exhibit distinct activation profiles and cytokine production capabilities.
- Understanding macrophage responses to stimuli is key to modulating immune responses.
Purpose of the Study:
- To compare the TNF production of alveolar macrophages (Am phi s), resident peritoneal macrophages (RPm phi s), and thioglycolate-elicited peritoneal macrophages (TGPm phi s).
- To investigate the differential responses of these macrophage populations to lipopolysaccharide (LPS), stimulated cell supernatant, and interferon gamma (IFN-gamma).
Main Methods:
- Isolation of Am phi s, RPm phi s, and TGPm phi s from C57BL/6 mice.
- Incubation of macrophages with LPS, stimulated cell supernatant, or IFN-gamma for 24 hours.
- Quantification of TNF in cell-free supernatants using enzyme-linked immunosorbent assay (ELISA).
Main Results:
- Am phi s produced 50-fold more TNF than RPm phi s and 5-fold more than TGPm phi s when stimulated with LPS.
- LPS alone maximally induced TNF production in Am phi s.
- RPm phi s and TGPm phi s required combined stimuli (LPS plus supernatant or IFN-gamma) for maximal TNF production.
- TGPm phi s demonstrated higher sensitivity to combined stimuli compared to other macrophage types.
Conclusions:
- Alveolar macrophages are inherently more responsive to LPS for TNF production compared to peritoneal macrophages.
- Peritoneal macrophage activation for TNF release is dependent on multiple signaling pathways.
- Macrophage heterogeneity influences their inflammatory cytokine output, with implications for targeted immunotherapies.