Inhibition of Immediate and Delayed Hypersensitivity in the Rabbit by 6-Mercaptopurine

Open Access
Publisher Website
Google Scholar
Abstract
Summary: Six-mercaptopurine (6-MP) was shown to exert both central and peripheral actions on immune reactions. Its central effects were inhibition of humoral antibody formation and suppression of delayed hypersensitivity. The antimetabolite also blocked the peripheral manifestations of immunity (skin reactions to antigens) without affecting the immune status of the animal. These various actions of 6-MP were brought out under selected conditions of timing, dosage and mode of antigen administration. The processes leading to the development of delayed hypersensitivity were found to be very sensitive to 6-MP; a 4-day course of the drug suppressed this response without inhibiting humoral antibody production or inflammatory responses. The suppression of skin reactions in hyperimmunized rabbits was presumably due to an anti-inflammatory effect of 6-MP; inhibition of the local passive Arthus reaction by 6-MP was a function of the amount of antibody in the test serum. Leukopenia or inanition could not explain these actions of 6-MP.