Differential effect of human chorionic gonadotrophin on lymphocyte proliferation induced by mitogens.

Human chorionic gonadotrophin (hCG) inhibits the lymphoproliferative responses of human peripheral blood mononuclear cells (PBM) to phytohaemagglutinin (PHA) and concanavalin A (Con A) at 10-50 IU of hCG/ml (P less than 0.05). hCG inhibited poorly the response of PBM to pokeweed mitogen (PWM) at concentration up to 100 IU/ml. When monocytes were removed from the PBM population with columns of Sephadex G10 the inhibitory effect of hCG on PHA- and Con A-induced lymphoproliferation was reduced, with inhibition occurring only at a level of 100 IU of hCG/ml. These results suggest that hCG does not inhibit equally the proliferative response of all lymphocyte subsets and further that cells of the monocyte/macrophage series may play a role in its action on lymphocyte proliferation.