The cellular basis for the generation of antigen-specific T8 suppressor cells with high doses of antigen has been studied. We separated the T4 subset of human T cells into T4+2H4+ and T4+2H4- subpopulations with a recently developed monoclonal anti-2H4 antibody. T8 cells could be consistently activated to suppress a primary anti-2,4-dinitrophenyl (DNP) antibody response in vitro with unfractionated T4 cells or with the T4+2H4+ subset but not the T4+2H4- subset. In contrast, the T4+2H4- subset functioned as the helper inducer for the anti-DNP antibody response. With keyhole limpet hemocyanin (KLH)-stimulated T4+2H4+ cells we could efficiently induce antigen-specific suppressor activity of fresh T8 cells. In contrast, the T4+2H4+ subset could not effect suppression in the absence of T8 cells. Our findings indicate that the T4+2H4+ subset of human T cells is the suppressor inducer of specific T8 cells in an antigen-specific DNP-KLH system.