Abstract
The antigen-recognition mechanism of T cells was reviewed from the standpoint of MHC-restriction. T cells recognize antigens presented by antigen-presenting cells in a MHC-restricted manner. CD4+ helper T cells recognize antigens with the context of MHC classⅡ molecules, and CD8+ cytotoxic T cells recognize antigens with MHC classⅠ molecules. The MHC classⅠ molecule is composed of α-chain and β2-microglobulin, and MHC classⅡ molecule is composed of α-chain and β-chain. The T cell antigen receptor is composed of α-chain and β-chain, or γ-chain and δ-chain, and CD3 complex. Antigens are processed and presented by antigen-presenting cells to T cells in the context of MHC molecules. Furthermore, costimulatory factors such as adhesion molecules and cytokines are required for the full activation of T cells. The biological significance of the T cell antigen recognition mechanism is discussed from the standpoint of clinical application.
