title: The clone size of peripheral CD8 T cells is regulated by TCR promiscuity.
abstract: Positive selection in the thymus and peripheral T cell survival depend on T cell receptor (TCR)-major histocompatibility complex (MHC) interactions, but it is not yet clear if both events follow exactly the same rules. We studied peripheral T cell survival and clone sizes in conditions of progressive reduction of restricting MHC-bearing cells or progressive ablation of different MHC molecules. Different CD8(+) T cell clones/polyclonal populations showed different survival and/or lymphopenia-driven proliferation requirements. We could correlate clone sizes to the capacity of each TCR to interact with different types of MHC complexes. Thus, although repertoire selection in the thymus is mainly conditioned by the affinity of TCR-MHC interactions, peripheral selection is determined by TCR cross-reactivity to environmental ligands.
authors.affiliation: Unité Biologie des Populations Lymphocytaires, Unité de Recherche Associé Centre National de la Recherche Scientifique 1961 Institut Pasteur, 75724 Paris Cedex 15, France.
authors.forename: Yi
authors.initials: Y
authors.lastname: Hao
authors.forename: Nicolas
authors.initials: N
authors.lastname: Legrand
authors.forename: Antonio A
authors.initials: AA
authors.lastname: Freitas
mesh_terms: D000818:Animals; D018956:CD5 Antigens / Q000096:biosynthesis; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D002470:Cell Survival / Q000276:immunology; D002478:Cells, Cultured; D002999:Clone Cells; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000235:genetics; D005260:Female; D006183:H-2 Antigens / Q000235:genetics; D064532:Histocompatibility Antigen H-2D; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism / Q000502:physiology*
chemical_list: D018956:CD5 Antigens; D004268:DNA-Binding Proteins; D006183:H-2 Antigens; D064532:Histocompatibility Antigen H-2D; C499308:Rag2 protein, mouse; D011948:Receptors, Antigen, T-Cell