Characterization of immunotrap assays for urokinase plasminogen activator and its inhibitors and measurements of these molecules in human plasma and mouse macrophage in culture.

1. Immunotrap assays that can measure the activities of urokinase-type plasminogen activator (uPA) and its inhibitors (PAIs) were characterized. 2. Both human plasma and mouse macrophages in culture were found to contain much higher inhibitor activity than uPA-like activity. 3. The balance between pro- and anti-fibrinolytic activities was quantitatively changed in the murine macrophages after the injection of thioglycollate. uPA-like materials were synthesized by the macrophages and secreted to the conditioned medium continuously, while PAI activity was unchanged during the same time period.