The antigen recognising receptor on the surface of T-cells. Heterodimeric (disulphide linked), one of the immunoglobulin superfamily of proteins, binds antigen in association with the major histocompatibility complex (MHC), leading to the activation of the cell.
There are two subunits (_ and _, 42-44 kD in mouse, 50-40 kD in humans), each with variable and constant regions, that are associated noncovalently with T3 (20-30 kD). A second heterodimer on CD3 cells with _ (35 kD in mice, 55 kD in humans) and _ (45 kD in mice, 40 kD in humans) chains is a second T-cell antigen receptor that is not MHC restricted. The __ T-cell receptors (TCRs) are formed on very early T-cells in the thymus.
(18 Nov 1997)