Contrasuppression. A novel immunoregulatory activity

Abstract

The authors have described an interaction between two T cell subsets that results in interference with the expression of Ly-1 -,2 + (Ly-2) T cell-mediated suppression. The authors refer to this novel immunoregulatory activity as contrasuppression. The T cell responsible for the induction of contrasuppression (inducer cell) expresses the phenotype Ly-1 -,2 +;I-J +;Qa-1 +. This phenotype distinguishes it from suppressor effector cells which the authors find to be I-J -. An I-J + soluble mediator from the contrasuppressor inducer cell acts on another cell (acceptor cell) that expresses the phenotype Ly-1 +;I-J +;Qa-1 +. This phenotype distinguishes it from T helper cells. Both the inducer cell (or its biologically active mediator) and its acceptor cell are required for the expression of contrasuppression. Because contrasuppressor cells can block the suppressive activity of cell-free mediators released by Ly-2 suppressor T cells, the mechanism of contrasuppression is either separate from or in addition to the inactivation of suppressor cells themselves. The potential importance of contrasuppressor activity in the regulation of suppressor T cell activity in allowing immunologic memory to be expressed and in permitting microenvironmental immune regulation is discussed.