Lymphokines and thrombosis. II. Procoagulant activity produced by human lymphocytes stimulated with concanavalin A (con-A).

Human lymphocytes stimulated with concanavalin-A produce a coagulant activity which decreases the clotting time as expressed through the recalcification time of citrated plasma, the partial thromboplastin time, the thrombin clotting time of citrated plasma and the thrombin clotting time of fibrinogen solutions. The culture supernatants of human lymphocytes stimulated with concanavalin-A also have a direct coagulant effect on human fibrinogen solution. They decrease the lag period of recalcification time of citrated plasma but do not modify the duration of polymerization as measured with a spectrophotometric method.