CD8+CD28- T suppressor cells and the induction of antigen-specific, antigen-presenting cell-mediated suppression of Th reactivity

Human CD8(+)CD28(-) suppressor T cells (Ts) are a subset of T cells generated in the course of in vitro and in vivo immunizations. Ts recognize MHC class I:peptide complexes and inhibit the reactivity of T helper cells (Th) with cognate antigen specificity. We have demonstrated for the first time that CD8(+)CD28(-) Ts represent a unique subset of regulatory cells that induces the differentiation of tolerogenic antigen-presenting cells, initiating a Suppressive loop which results in the induction and spreading of Th unresponsiveness.