Concanavalin A is mitogenic for resident peritoneal macrophages
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Abstract:
Con A, a known T-cell mitogen, is also mitogenic for resident peritoneal macrophages. The stimulated cells morphologically resemble macrophages and are actively phagocytic. The concentration of con A (30 micrograms/ml) required to stimulate 3H-TdR incorporation is ten times that required for T-cell activation. Con A must be present throughout the entire culture period to produce the maximum effect, and con A-depleted supernatant fluids from con A-stimulated cells cannot replace the con A requirement. Stimulation of 3H-TdR incorporation occurs after a 48-hour lag period and is maximal on the fifth to seventh day of culture. At the peak of the response, 20-30% of the macrophages can be stimulated to incorporate 3H-TdR, but little or no increase in the total number of cells present in the culture occurs. This and pulse-chase experiments indicate that only a single cycle of replication occurs in the stimulated cells. Con A-responsive peritoneal macrophages appear to be a distinct subpopulation and might play a different role in the interaction with T cells and B cells in the immune response than the con A-non-responsive cells.
Insights
Concanavalin A (Con A) stimulates resident peritoneal macrophages, inducing phagocytosis and DNA synthesis. These Con A-responsive macrophages represent a distinct subpopulation involved in immune responses.
Area of Science:
- Immunology
- Cell Biology
Background:
- Concanavalin A (Con A) is a known T-cell mitogen.
- Resident peritoneal macrophages exhibit responses to Con A stimulation.
Purpose of the Study:
- To investigate the mitogenic effects of Con A on resident peritoneal macrophages.
- To characterize the response of macrophages to Con A, including proliferation and phagocytic activity.
Main Methods:
- Culture of resident peritoneal macrophages.
- Stimulation with Concanavalin A (Con A).
- Assessment of 3H-TdR incorporation and phagocytic activity.
Main Results:
- Con A stimulates macrophages, enhancing their phagocytic capacity.
- Macrophage 3H-TdR incorporation requires higher Con A concentrations and prolonged exposure compared to T-cells.
- A 48-hour lag period precedes maximal DNA synthesis, with a single replication cycle observed.
- Con A-responsive macrophages constitute a distinct subpopulation.
Conclusions:
- Resident peritoneal macrophages are responsive to Con A, exhibiting morphological and functional changes.
- The response involves a distinct subpopulation of macrophages with potential unique roles in immune interactions.
- Further research is needed to elucidate the specific functions of Con A-responsive macrophages in T-cell and B-cell interactions.