The repertoire of T cells shaped by a single MHC/peptide ligand.
Although the thymus produces many immature thymocytes, few of these cells mature. Positive selection has been thought to limit thymocyte development. In thymuses expressing a single MHC/peptide combination, however, surprisingly large numbers of thymocytes are selected to mature. Many of these react with the selecting MHC, bound to other self-peptides. Therefore, the number of thymocytes that mature is limited by the fact that positively selected cells die because they react too well with MHC bound to self-peptides that are not identical to those involved in positive selection. T cells that mature in thymuses expressing a single MHC/peptide ligand react frequently with foreign MHC, suggesting that the repertoire of alpha beta receptors may be more biased toward reaction with MHC than was previously thought.
Ignatowicz
L
L
Department of Medicine, National Jewish Center for Immunology and Respiratory Medicine, University of Colorado Health Sciences Center, Denver, 80206, USA.
Kappler
J
J
Marrack
P
P
D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000276:immunology*; D000944:Antigens, Differentiation, B-Lymphocyte / Q000235:genetics / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism / Q000648:ultrastructure; D005786:Gene Expression Regulation / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000235:genetics / Q000276:immunology* / Q000502:physiology*; D006825:Hybridomas; D008285:Major Histocompatibility Complex / Q000502:physiology*; D051379:Mice; D008815:Mice, Inbred Strains; D008822:Mice, Transgenic; D010455:Peptides / Q000276:immunology / Q000378:metabolism; D011485:Protein Binding / Q000276:immunology; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology* / Q000276:immunology / Q000648:ultrastructure; D019076:Transgenes / Q000502:physiology
D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte; D000949:Histocompatibility Antigens Class II; D010455:Peptides; D016693:Receptors, Antigen, T-Cell, alpha-beta; C045084:invariant chain