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Alteration of some functional and metabolic characteristics of resident mouse peritoneal macrophages by lymphocyte
Abstract:
Resident mouse peritoneal macrophages were incubated in Sephadex G-100 fractions of supernates from concanavalin A-stimulated lymphocytes. A significant effect of the lymphocyte supernatant fractions containing mediators on macrophage 5'-nucleotidase, glucose-1 14C oxidation, cell maintenance, and migration is reported. The 5'-nucleotidase was depressed to an extent similar to that seen in activated macrophages obtained from Listeria-infected mice. On the other hand, glucose-1-14C oxidation was enhanced, but not to the same degree as seen in the counterparts in vivo. Whereas migration inhibitory factor (MIF) and cell adherence-augmenting activity were found in a number of adjacent fractions, the metabolic effects were found predominantly in a single fraction. Resident peritoneal macrophages or those elicited by the injection of a lymphocyte-derived chemotactic factor were more responsive with respect to the biochemical changes than caseinate-elicited macrophages. On the other hand, caseinate-elicited macrophages appeared to be more sensitive with respect to the effects of mediator(s) on cell retention. A possible dissociation between MIF and cell-adherence augmenting activity, on the one hand, and the entities that stimulate glucose-1-14C oxidation is reported, based on fractionation studies, and loss of the latter activity upon storage of lymphocyte supernates.
Insights
Lymphocyte mediators significantly impact macrophage function, altering enzyme activity and glucose metabolism. These findings reveal distinct effects on different macrophage types, suggesting complex immune regulation.
Area of Science:
- Immunology
- Cell Biology
Background:
- Lymphocytes produce mediators that influence macrophage behavior.
- Macrophage activation is crucial for immune responses.
Purpose of the Study:
- To investigate the effects of lymphocyte-derived mediators on macrophage functions.
- To characterize the specific biochemical and functional changes in macrophages exposed to these mediators.
Main Methods:
- Incubation of resident mouse peritoneal macrophages with Sephadex G-100 fractions from concanavalin A-stimulated lymphocyte supernates.
- Assay of macrophage 5'-nucleotidase activity, glucose oxidation, cell maintenance, and migration.
- Fractionation studies to isolate active mediator components.
Main Results:
- Lymphocyte mediators significantly altered macrophage 5'-nucleotidase activity (depressed) and glucose oxidation (enhanced).
- Migration inhibitory factor (MIF) and cell adherence-augmenting activity were observed, but metabolic effects localized to a distinct fraction.
- Resident and chemotactic factor-elicited macrophages showed greater responsiveness to metabolic changes than caseinate-elicited macrophages.
Conclusions:
- Lymphocyte mediators exert diverse effects on macrophage metabolism and function.
- Distinct mediator entities may be responsible for metabolic changes versus MIF and cell adherence activities.
- Macrophage responsiveness to these mediators varies depending on their activation state.