Functional Characterization of Hapten-Specific Suppressor Cells

T cells From animals suppressed against a given hapten, trinitrophenyl (TNP), were analysed for their capacity to inhibit the humoral B-cell response against the hapten and/or a complex antigen, horse erythrocytes (HRBC), coupled or not 10 the hapten. As expected, suppression of the response to HRBC in all experiments required coupling to TNP. However, the suppressing capacity of the T cells varied with the stage of the B cells, with no detectable suppression occurring if already primed carrier-specific B cells were used. Hapten-specific T helper cells could, however, be induced in hapten-suppressed mice, when hapten-carrier conjugates were used as immunogen. Under these conditions normal efficiency of induction of carrier-specific T helper cells was observed, and this probably also applied to hapten-specific T helper cells to the same extent. This assumption was strengthened by using the hapten-binding capacity of the suppressor T cells and Lyt-l/2-specific sera to subdivide physically helper and suppressor function.