The role of cell surface recognition structures in the initiation of MHC-unrestricted 'promiscuous' killing by T cells.

CD3+ T cells mediate relatively promiscuous patterns of major histocompatibility complex (MHC)-unrestricted target cell lysis following activation. Cell-cell contact between target and effector cells is essential in this form of cytotoxicity. Although the T-cell receptor (TCR)-CD3 molecular complex can transmit signals that initiate MHC unrestricted T-cell killing, recognition of targets by the TCR is not essential for this form of cytotoxicity. In this review by Dwain Thiele and Peter Lipsky, a model of the triggering of T cells to effect MHC-unrestricted cytotoxicity is proposed.