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Macrophage plasminogen activator: induction by products of activated lymphoid cells
Abstract:
Macrophages obtained from the peritoneal cavity of untreated mice do not ordinarily synthesize plasminogen activator. However, induction of enzyme synthesis and secretion occurs when such macrophages are cultured in presence of conditioned medium from Con A-stimulated spleen cells. Plasminogen activator production by macrophages from endotoxin or thioglycollate medium-injected mice, which spontaneously secrete substantial amounts of the enzyme, is also markedly increased in presence of such conditioned medium. These results suggest that macrophage plasminogen activatory production may be regulated in part by lymphocytes. They provide further evidence to link macrophage plasminogen activator with cell migration and inflammation, and also support the view that in macrophages, as in certain other cell types, synthesis and secretion of this enzyme are under hormonal control.
Insights
Lymphocytes regulate macrophage plasminogen activator production, influencing cell migration and inflammation. This suggests hormonal control over enzyme synthesis and secretion in macrophages.
Area of Science:
- Immunology
- Cell Biology
Background:
- Macrophages typically do not synthesize plasminogen activator.
- Certain conditions induce plasminogen activator secretion in macrophages.
Purpose of the Study:
- To investigate the regulation of plasminogen activator production in macrophages.
- To explore the role of lymphocyte-derived factors in macrophage activation.
Main Methods:
- Culturing macrophages from untreated, endotoxin-injected, or thioglycollate-injected mice.
- Incubating macrophages with conditioned medium from Con A-stimulated spleen cells.
- Measuring plasminogen activator synthesis and secretion.
Main Results:
- Conditioned medium from Con A-stimulated spleen cells induced plasminogen activator synthesis in untreated macrophages.
- The conditioned medium further increased enzyme production in macrophages already secreting plasminogen activator.
- Macrophage plasminogen activator production appears to be influenced by lymphocyte-derived factors.
Conclusions:
- Macrophage plasminogen activator production is, in part, regulated by lymphocytes.
- This enzyme is linked to macrophage cell migration and inflammatory processes.
- Evidence suggests hormonal control over plasminogen activator synthesis and secretion in macrophages.