Human monocytes release plasma serine protease inhibitors in vitro.

The ability of human peripheral blood monocytes to secrete plasma serine protease inhibitors was studied. Monocytes from blood obtained from healthy young adult volunteers were cultured for up to 36 h with and without lipopolysaccharide from Escherichia coli. The concentrations of plasma serine protease inhibitors in monocyte culture supernatants were measured by using rocket immunoelectrophoresis. The study showed that human monocytes stimulated with lipopolysaccharide in vitro release antithrombin III, C1 esterase inhibitor, alpha 2-antiplasmin, and alpha 2-macroglobulin.