Suppressor T cells and suppressor macrophages induced by Corynebacterium parvum

Corynebacterium parvum, injected intravenously into C57B1/6 mice (H-2^b) previously alloimmunized with P815 (H-2^d) mastocytoma cells, generated splenic suppressor cells that inhibited the development of primary cytotoxic lymphocytes in vitro. These suppressor cells differed from those generated by intravenous C. parvum injection of naive C57B1/6 mice. The former suppressor cells were effectively induced by administration of 700 μg of C. parvum whereas the latter suppressor cells were dependent upon higher doses (1400 μg) of adjuvant for their activation. Furthermore, suppressor cells generated in alloimmunized mice could only suppress C57B1/6 anti-P815 in vitro cytotoxic responses whereas suppressor cells generated in naive mice could suppress C57B1/6 anti-CBA (H-2^k) responses as well. Suppressor cells were not H-2 restricted in their action. Fractionation of spleens from alloimmunized, C. parvum-treated mice revealed the presence of suppressor T cells and suppressor macrophages. We were unable, however, to determine which cell was responsible for “antigen specificity” of suppression since the fractionation procedures seemed to trigger both suppressor cell types prior to adding them to the primary culture.