The effect of protease inhibitors on leucocyte migration inhibition to tuberculin extract (P.P.D.).

The protease inhibitors, Epsilon Amino Caproic Acid (E.A.C.A.) and Aprotinin were found to significantly increase the inhibition produced by P.P.D. in the Leucocyte Migration Test (L.M.T.). Dose-response curves showed that the most effective concentrations were for E.A.C.A. 0.01 M and Aprotinin 100 I.U./ml. In a series of 29 subjects with a range of Heaf reactivity this finding was consistent providing that there was a significant inhibition to P.P.D. alone. At these concentrations, cell viability was unaffected and the effect of the drugs could be reversed by washing. The exact mode of action of these inhibitors in the L.M.T. requires further elucidation.