Immunomodulating activities on cellular cytotoxicity and the blast transformation of human lymphocytes by 10-[n-(phthalimido)alkyl-2-substituted-10H-phenothiazines and 1-(2-chloroethyl)-3-(2-substituted-10 H-phenothiazin-10-yl)alkyl-1-ureas.

Phenothiazines, 10-[n-(phthalimido)alkyl-2-substituted-10H- phenothiazines, and 1-(2-chloroethyl)-3-(2-substituted-10H-phenothiazin-10-yl)alkyl-1- ureas were investigated for their effects on antibody-dependent cellular cytotoxicity (ADCC), natural killer (NK) cells and the blast transformation of human peripheral blood mononuclear cells. All of the compounds dose-dependently suppressed mitogen-stimulated T cell proliferation. In contrast, a strong enhancing effect on NK cell activity was detected mostly in the case of 1-(2-choroethyl)-3-(2-substituted-10H-phenothiazin-10-yl)alk yl-1-ureas and their related compounds. The stimulating effect directly influenced the NK cells and was demonstrated at all tested concentrations.