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[Antigen-recognition mechanism of T cells]
1Department of Immunology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
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 class II molecules, and CD8+ cytotoxic T cells recognize antigens with MHC class I molecules. The MHC class I molecule is composed of alpha-chain and beta 2-microglobulin, and MHC class II molecule is composed of alpha-chain and beta-chain. The T cell antigen receptor is composed of alpha-chain and beta-chain, or gamma-chain and delta-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.