Plasminogen activator in psoriatic scales is of the tissue-type PA as identified by monoclonal antibodies.

Extracts of scale from four patients with psoriasis all contained plasminogen activator. All plasminogen activator activity was of the tissue-type (t-PA) as judged from the following criteria: all enzyme activity was inhibited by a monoclonal antibody against human t-PA, while there was no measurable inhibition by a monoclonal antibody against human urokinase-type plasminogen activator (u-PA); as determined by zymography the extracts contained one type of plasminogen activator which had an electrophoretic mobility identical to that of purified t-PA; this plasminogen activator was removed by passage through a Sepharose column coupled with a monoclonal antibody against t-PA, but not by passage through a column coupled with a monoclonal antibody against u-PA. On a molar basis the detection limit for u-PA was 10% of that of t-PA present.