Allograft cytotoxicity co-operation between alloimmune T cells and macrophages.

T cells from the spleens of C57BL 10 (H-2b) mice 7-12 days after immunization with P815Y (H-2d) mastocytoma cells have been shown to co-operate synergistically with an adherent component of non-immune starch induced peritoneal cells in the cytostasis of target cells. Although significant values for synergy could be obtained using the (125I) UdR incorporation assay to measure cytostasis, normal peritoneal cells were incapable of co-operating with T cells in cytolysis as measured by 51Cr release from pre-labelled target cells. Initially, the synergistic interaction was immunologically specific, but non-specific activity could be induced by challenge with specific antigen.