[Action of ketotifen on the mitogen-evoked proliferative response of human mononuclear cells].

Ketotifen at low concentrations (5 and 50 microns) potentiated and at high ones (250 and 500 microM) blocked the proliferative response of human peripheral blood mononuclear cells ( NNC ) induced by PHA. The proliferative response was evaluated by 3H-thymidine incorporation into the cells. At doses inhibiting proliferative response to PHA ketotifen blocked both Con A-induced and Pokeweed mitogen-induced proliferations of MNC. At tested concentrations ketotifen inhibited and at the highest concentration (250 microM) blocked PHA-induced increase of protein synthesis in MNC evaluated by incorporation of 14C-L-leucine into the cells. The presented data showed that ketotifen acted not on the inductive step of the proliferative response but on the steps preceding the cell shift into S-phase.