Immunosuppression by platinum diamines.

Platinum diamine dichloride and tetrachloride inhibit the formation of antibody-forming cells in the mouse spleen after injection of sheep red cells. The dichloride is the more effective agent. It acts best when given 2 days after the antigen, which suggests that cells are more sensitive to its action when they are rapidly proliferating than when they are resting. Its dose-response curve is exponential, suggesting that its action is like that of an alkylating agent. Platinum ethylene diamines were relatively ineffective in this system.