Immunological identification of plasminogen activators in normal and malignant tissues of the oral cavity in man.

Plasminogen-activator activity was examined qualitatively in normal and malignant mucosa of the oral cavity in humans, using an immunological histochemical fibrin slide technique. No fibrinolytic activity was observed in sections of normal mucosa when monospecific antibodies against a melanoma cell activator (anti-MA) were added. Antibodies against urokinase (anti-UK) did not react on the fibrinolytic activity which indicates that the activator is of tissue type. In malignant tissue, fibrinolytic activity was completely blocked by a mixture of anti-MA and anti-UK.