Assembly of the T Cell Receptor/CD₃ Complex

Abstract

The human T cell receptor for antigens is a multichain cell surface receptor consisting of variable (TCR -α/β or TCR -γ/δ and constant elements (CD3 — γ δεζThe exquisite specificity for antigen plus MHC (or CD1) resides in the variable regions of the TCR α/β (or TCR — γ /δ) glycoproteins (1, 2, 3). Since T cell receptors and MHC products (4) (or CD1 glycoproteins (5)) are anchored in the plasma membrane of T lymphocytes and antigen presenting cells, respectively, antigen recognition takes place on the interface between the two cells. A localized and TCR-independent set of adhesion events provides a stablizing environment for the subtle ternary interaction which is dependent upon the fine specificity of its participants. Thus, antigen recognition by T cells is a carefully orchestrated and tightly regulated event.