Macrophages are activated by endocytosis of α2-macroglobulin-protease complexes to produce neutral proteases
At sites of inflammation, proteases are released by inflammatory and tissue cells. The activation of the complement, the coagulation and the fibrinolytic systems produce additional proteases. Active proteases become inactivated by various inhibitors in the circulation and in tissues. Among the plasma protease inhibitors, alpha1-antitrypsin and alpha2-macroglobulin (α2M) are quantitatively the most important ones. In the circulation, proteases bound to alpharantitrypsin are transferred to α2M1. The α2M-protease complexes are then taken up by the fixed tissue macrophages in liver and spleen1,2. In the experiments summarized in this paper, we have studied the effect of α2M-trypsin complexes on macrophages in vitro.
KeywordsPlasminogen Activator Synovial Fluid Neutral Protease Fluid Synovial Fluid Human Synovial Fluid
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