Evidence for splenic suppressor cells in C3H/He, T cell-deprived C3H/He, and nude mice bearing a 3-methylcholanthrene-induced fibrosarcoma

ABSTRACT-Suppressor cells were demonstrated in the spleens of C3H/He mice carrying 3-methYlcholanthrene-induced fibrosar-comas. These cells inhibited the in vitro reactivity of normal lymphocytes to Too and B-cell mitogens. They disappeared within a few days after the tumor was surgically removed. Pretreatment of spleen cells (SpC) from tumor-bearing (TB) mice with either iron and a magnet, antiserum against Thy 1.2 antigen plus comple-ment, or antiserum against immunoglobulin plus complement demonstrated that the suppressor cells were adherent, non-Too cells bearing immunoglobulin at their surfaces. The suppressive effect could still be demonstrated by addition of SpC from TB mice 24 or 48 hours after phytohemagglutinin stimulation of nor-mal SpC. SpC from TB C3H/He mice inhibited mitogen-induced stimulation of both C3H/He and DBA/2 lymphocytes. In T-cell-deprived TB C3H/He mice, suppressor cells were also observe