Concentrations of levamisole required for enhanced proliferation of human lymphocytes and phagocytosis by macrophages.

We studied the in vitro effects of levamisole on phagocytosis by macrophages and on proliferation of lymphocytes obtained from human peripheral blood. It was observed that levamisole directly stimulated phagocytosis in a lymphocyte-free system. Enhancement was optimal at a concentration that inhibited antigen- or mitogen-induced stimulation of sensitive lymphocytes. Lower concentrations of levamisole enhanced the proliferative lymphocyte response.