Mechanisms of regulation of cell-mediated immunity. VII. Suppressor T cells induced by suboptimal doses of antigen plus an I-J-specific allogeneic effect

Intravenous injection of 0.01 mM 2,4,6-trinitrobenzene sulfonic acid- derivatized syngeneic lymphoid cells generates a Thy-1-positive, antigen-specific suppressor cell for contact sensitivity which requires an I-J allogeneic effect to become fully activated. It is necessary and sufficient for all allogeneic effect to be directed solely against the suppressor cell, and once activated, the cell can suppress in an H-2- unrestricted fashion. The results are discussed in the framework of entry into the suppressor pathway, the allogeneic effect as a reflection of normal physiologic processes, and the importance of I-J as a receptor and signal among cells in the suppressor pathway.