Isoantiserum-augmented development of lymphocyte-mediated cytotoxicity.

Passive administration of anti-P-814 isoantiserum (IS) with P-815 mastocytoma was shown to augment the development of T-lymphocyte-mediated cytotoxicity (LMC). The LMC activity augmented by IS was specific to immunizing tumor cells, but required the simultaneous administration of P-815 tumor cells and anti-P-815 serum, suggesting that the antigen-antibody complex is involved in the development of specific cytotoxic T cells. The serum component responsible for augmented development of LMC activity appeared to be IgM in that the augmenting activity fractionated in the void volume of a G-200 Sephadex column and appears very early after immunization. Our experimental results suggest the development of specific T-cell cytotoxicity can be directly regulated by specific IgM antibodies.