title: An incremental increase in the complexity of peptides bound to class II MHC changes the diversity of positively selected alpha beta TCRs.
abstract: Positive selection of the normal repertoire of TCRs results from low-avidity interactions with a set of self-peptides bound to the MHC molecules expressed by thymic epithelial cells. The contribution of the individual peptide to positive selection remains a matter of debate. Here, for the first time, we show that two covalent class II MHC-peptide complexes positively select different TCRs expressing a common transgenic TCRbeta-chain and endogenous TCRalpha-chains. Simultaneous expression of both A(b)-peptide complexes changed the diversity of positively selected TCRs, indicating an additive and possibly synergistic effect of various peptides in this process.
authors.affiliation: Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA 30912, USA.
authors.forename: R
authors.initials: R
authors.lastname: Pacholczyk
authors.forename: P
authors.initials: P
authors.lastname: Kraj
authors.forename: L
authors.initials: L
authors.lastname: Ignatowicz
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D002469:Cell Separation; D003433:Crosses, Genetic; D005333:Fetus; D005434:Flow Cytometry; D005786:Gene Expression Regulation / Q000276:immunology; D015332:Gene Rearrangement, alpha-Chain T-Cell Antigen Receptor / Q000235:genetics / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000096:biosynthesis / Q000378:metabolism*; D006825:Hybridomas; D046911:Macromolecular Substances; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D009924:Organ Culture Techniques; D010446:Peptide Fragments / Q000096:biosynthesis / Q000276:immunology* / Q000378:metabolism*; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D000949:Histocompatibility Antigens Class II; D046911:Macromolecular Substances; D010446:Peptide Fragments; D016693:Receptors, Antigen, T-Cell, alpha-beta