Cell surface alpha sub(1)-protease inhibitor on human peripheral mononuclear cells in culture

The authors have studied expression of alpha sub(1)-protease inhibitor ( alpha sub(1)-Pl) by human mononuclear cells. The data are consistent with the interpretation that human mononuclear phagocytes synthesize and secrete alpha sub(1)-Pl. When protein synthesis is inhibited, mitogenic stimuli may provoke release of previously synthesized alpha sub(1)-Pl from mononuclear phagocytes. Secreted alpha sub(1)-Pl then may bind to specific lymphocyte cell surface receptors. This pattern of alpha sub(1)-Pl synthesis, secretion, binding, and expression on lymphoid cell surfaces appears to be a common characteristic of many immunologic reactions in vitro.