Hydantoin immunosuppression and carcinogenesis.

The immunological response of mice submitted to hydantoin treatment was determined. Hydantoin reduced the absolute number of spleen cells in treated animals and did not modify spleen cells reactivity to concanavalin A, although the response to SRBC challenge, as measured by the Jerne plaque-forming cell technique, was significantly decreased. Following these findings, the influence of hydantoin on carcinogenesis was evaluated by using the model of urethane-induced lung adenomas in SWR mice. Treatment with hydantoin significantly reduced the incidence of the induced adenomas. We confirmed that hydantoin modifies the immune response of the host mainly by depressing its humoral function and we have shown that this effect was associated with an inhibitory effect on tumour induction.