Interferon-gamma plays a crucial role in T lymphocyte reaction against alloantigens.

In this study we report that addition to mixed lymphocyte reactions of monoclonal antibodies to interferon-gamma inhibits alloantigen recognition and induction of cytotoxic T lymphocytes by inducing early and highly effective suppressor T lymphocytes. This inhibitory activity is not confined to in vitro models, since daily local injection of these antibodies in CBA/J mice blocks the rejection of fully allogeneic tumor cells consistently displayed by untreated CBA/J mice.