EFFECT OF MURINE INTERFERON-ALPHA BETA ON TUMOR-INDUCED SUPPRESSOR FUNCTION/

T-lymphocyte-mediated immunosuppression has been described in several animal models and in man. In animal models, T-cell-mediated immunosupp ression can hasten the development of cancers, permit the growth of tu mors in immunocompetent hosts, and inhibit otherwise effective antitum or immunotherapy. Cyclophosphamide can abrogate the T-cell-mediated im munosuppression. However, inappropriately administered cyclophosphamid e can adversely affect antitumor immunity. On the basis of data showin g that interferon alpha/beta (IFN alpha/beta) and IFN beta selectively abrogate the T-cell-mediated dinitrofluorobenzene-specific suppressor function, we investigated the efficacy of purified murine IFN alpha/b eta in manipulating tumor-induced T-cell-mediated immunosuppression in the well-characterized P815 mastocytoma model. In this model, generat ion of cytotoxicity in vitro and its inhibition by T cells correlates with antitumor immunity in vivo. We report that IFN alpha/beta selecti vely diminishes the generation of tumor-induced suppressor activity.