title: Generation of Peptides That Promote Positive Selection in the Thymus.
abstract: To establish an immunocompetent TCR repertoire that is useful yet harmless to the body, a de novo thymocyte repertoire generated through the rearrangement of genes that encode TCR is shaped in the thymus through positive and negative selection. The affinity between TCRs and self-peptides associated with MHC molecules determines the fate of developing thymocytes. Low-affinity TCR engagement with self-peptide-MHC complexes mediates positive selection, a process that primarily occurs in the thymic cortex. Massive efforts exerted by many laboratories have led to the characterization of peptides that can induce positive selection. Moreover, it is now evident that protein degradation machineries unique to cortical thymic epithelial cells play a crucial role in the production of MHC-associated self-peptides for inducing positive selection. This review summarizes current knowledge on positive selection-inducing self-peptides and Ag processing machineries in cortical thymic epithelial cells. Recent studies on the role of positive selection in the functional tuning of T cells are also discussed.
authors.affiliation: Division of Experimental Immunology, Institute of Advanced Medical Sciences, University of Tokushima, Tokushima 770-8503, Japan.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Takada
authors.affiliation: Division of Experimental Immunology, Institute of Advanced Medical Sciences, University of Tokushima, Tokushima 770-8503, Japan.
authors.forename: Kenta
authors.initials: K
authors.lastname: Kondo
authors.affiliation: Division of Experimental Immunology, Institute of Advanced Medical Sciences, University of Tokushima, Tokushima 770-8503, Japan takahama@genome.tokushima-u.ac.jp.
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Takahama
mesh_terms: D000818:Animals; D017951:Antigen Presentation; D001324:Autoantigens / Q000276:immunology; D002454:Cell Differentiation; D060966:Clonal Selection, Antigen-Mediated; D004848:Epithelium / Q000276:immunology*; D006649:Histocompatibility Antigens / Q000378:metabolism; D006801:Humans; D010446:Peptide Fragments; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism*; D013601:T-Lymphocytes / Q000276:immunology*; D013950:Thymus Gland / Q000502:physiology*
chemical_list: D001324:Autoantigens; D006649:Histocompatibility Antigens; D010446:Peptide Fragments; D011948:Receptors, Antigen, T-Cell