ABSTRACT
It is shown that the replacement of the ethyl or methyl radical in the molecules of aethaperazine or metherazine with the adamantyl one results in the appearance of a singular immunotropic activity. Such a drug (adapiprazine) exerts an immunodepressive action both on the primary and secondary response of the mice immunized with sheep erythrocytes. The immunodepressive action of adapiprazine is manifest with a low-dosage optimum introduced before immunization. In analogous conditions aethaperazine and metherazine fail to display any immunodepressive action. Adapiprazine arrests the rejection of a skin allotrasplant in mice differing from the donors in the presence of a strong histocompatibility locus. In in vitro tests adapiprazine in a concentration of 10(-5) mol and less has no effect on the spontaneous migration of leucocytes in the capillary, nor upon the process of immune roset-formation.