Regulation of the plasminogen activator activity of macrophage tumor cell lines.

Four murine monocyte-macrophage cell lines, WEHI-3, J774, RAW 264.10 and PU5-1.8, synthesize and secrete the proteolytic enzyme, plasminogen activator. Lymphocyte conditioned medium, 12-0-tetradecanoyl-phorbol-13-acetate and Concanavalin A enhance the enzyme activity of these lines, while low concentrations of anti-inflammatory glucocorticoids and also cholera toxin reduce the enzyme activity. These observations are similar to those found for mouse peritoneal exudate macrophages. It is suggested, therefore, that these cell lines might be useful models to delineate the cellular mechanisms involved in the control of the synthesis and secretion of macrophage plasminogen activator and of other macrophage secretory products, particularly those resulting from lymphocyte-macrophage interaction.