Coexistence of helper and suppressor activities in carrier-primed spleen cells.

Both helper and suppressor activities for an in vitro IgG anti-hapten (Lac) response to Lac-HRBC were demonstrated in the same population of carrier (HRBC)-primed spleen cells. The relative radiosensitivity of suppressor activity permitted the selective removal of suppression and the demonstration of help. Both activities appear to be T cell-dependent and antigen-specific. Dilution analysis showed that help and suppression are mediated by distinct populations of cells.