T-cell regulation of pokeweed-mitogen-induced polyclonal immunoglobulin production in mice. II. Mechanism of the induction of suppressor T cells.

The regulation of pokeweed-mitogen (PWM) induced polyclonal immunoglobulin (Ig) production by suppressor T cells was investigated in mice. Generation of Ig-producing cells in PWM-stimulated culture was helped by T cells and the helper activity was markedly augmented by X-irradiation, suggesting that the suppressor cells which may coexist in the helper source were abolished by X-irradiation. Present study also provided direct evidence for the involvement of suppressor cells in PWM-induced Ig production. Thus, suppressor cells could be induced by prestimulation of splenic T cells with high doses of PWM for 3-4 days. Both the precursor and effector suppressor T cells in this system were found to be Lyt 1- 2+. It was further shown that although the Lyt 1- 2+ subset could be directly stimulated by PWM to generate suppressor cells, the presence of Lyt 1+ 2- cells in the culture markedly enhanced the generation of Lyt 1- 2+ suppressor cells.