title: Functional evidence for TCR-intrinsic specificity for MHCII.
abstract: How T cells become restricted to binding antigenic peptides within class I or class II major histocompatibility complex molecules (pMHCI or pMHCII, respectively) via clonotypic T-cell receptors (TCRs) remains debated. During development, if TCR-pMHC interactions exceed an affinity threshold, a signal is generated that positively selects the thymocyte to become a mature CD4(+) or CD8(+) T cell that can recognize foreign peptides within MHCII or MHCI, respectively. But whether TCRs possess an intrinsic, subthreshold specificity for MHC that facilitates sampling of the peptides within MHC during positive selection or T-cell activation is undefined. Here we asked if increasing the frequency of lymphocyte-specific protein tyrosine kinase (Lck)-associated CD4 molecules in T-cell hybridomas would allow for the detection of subthreshold TCR-MHC interactions. The reactivity of 10 distinct TCRs was assessed in response to selecting and nonselecting MHCII bearing cognate, null, or "shaved" peptides with alanine substitutions at known TCR contact residues: Three of the TCRs were selected on MHCII and have defined peptide specificity, two were selected on MHCI and have a known pMHC specificity, and five were generated in vitro without defined selecting or cognate pMHC. Our central finding is that IL-2 was made when each TCR interacted with selecting or nonselecting MHCII presenting shaved peptides. These responses were abrogated by anti-CD4 antibodies and mutagenesis of CD4. They were also inhibited by anti-MHC antibodies that block TCR-MHCII interactions. We interpret these data as functional evidence for TCR-intrinsic specificity for MHCII.
authors.affiliation: Department of Immunobiology, The University of Arizona College of Medicine, Tucson, AZ 85724;
authors.forename: Heather L
authors.initials: HL
authors.lastname: Parrish
authors.affiliation: Department of Immunobiology, The University of Arizona College of Medicine, Tucson, AZ 85724; The Arizona Center on Aging, The University of Arizona College of Medicine, Tucson, AZ 85724;
authors.forename: Neha R
authors.initials: NR
authors.lastname: Deshpande
authors.affiliation: Department of Immunobiology, The University of Arizona College of Medicine, Tucson, AZ 85724;
authors.forename: Jelena
authors.initials: J
authors.lastname: Vasic
authors.affiliation: Department of Immunobiology, The University of Arizona College of Medicine, Tucson, AZ 85724; The Arizona Center on Aging, The University of Arizona College of Medicine, Tucson, AZ 85724; The BIO-5 Institute, The University of Arizona College of Medicine, Tucson, AZ 85724 mkuhns@email.arizona.edu.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Kuhns
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017951:Antigen Presentation; D000941:Antigens / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D016466:CHO Cells; D002460:Cell Line; D002462:Cell Membrane / Q000276:immunology; D018920:Coculture Techniques; D003412:Cricetulus; D015332:Gene Rearrangement, alpha-Chain T-Cell Antigen Receptor; D015333:Gene Rearrangement, beta-Chain T-Cell Antigen Receptor; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D006825:Hybridomas; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / Q000235:genetics / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D018448:Models, Immunological; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000276:immunology; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000276:immunology; D017384:Sequence Deletion; D037182:T-Cell Antigen Receptor Specificity
chemical_list: D000941:Antigens; D000949:Histocompatibility Antigens Class II; C474482:I-A(b) antigen, mouse; C024138:I-E-antigen; D010455:Peptides; D016693:Receptors, Antigen, T-Cell, alpha-beta; D011993:Recombinant Fusion Proteins; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck)
keywords: CD4; Lck; MHC; TCR; restriction
references.citation: Cell Mol Life Sci. 2014 Aug;71(16):3059-68
references.pmid: 24633202
references.citation: Immunol Cell Biol. 1998 Feb;76(1):34-40
references.pmid: 9553774
references.citation: Eur J Immunol. 2014 Jul;44(7):1936-46
references.pmid: 24723377
references.citation: Immunol Rev. 2012 Nov;250(1):49-60
references.pmid: 23046122
references.citation: Immunity. 2015 Nov 17;43(5):859-69
references.pmid: 26522985
references.citation: Nat Immunol. 2009 Feb;10(2):143-7
references.pmid: 19148199
references.citation: Immunity. 1996 Aug;5(2):125-35
references.pmid: 8769476
references.citation: Cell. 1990 Mar 9;60(5):755-65
references.pmid: 2107025
references.citation: Immunity. 1997 Apr;6(4):389-99
references.pmid: 9133418
references.citation: Cell. 1993 Aug 27;74(4):633-43
references.pmid: 8358792
references.citation: Proc Natl Acad Sci U S A. 1999 Aug 17;96(17):9781-6
references.pmid: 10449771
references.citation: Trends Immunol. 2012 Sep;33(9):429-36
references.pmid: 22771140
references.citation: Cell. 2013 Sep 12;154(6):1326-41
references.pmid: 24034254
references.citation: Cell. 1997 Mar 7;88(5):627-36
references.pmid: 9054502
references.citation: J Immunol. 2011 May 15;186(10 ):5823-32
references.pmid: 21490152
references.citation: J Immunol. 2008 Dec 15;181(12):8568-75
references.pmid: 19050276
references.citation: Mol Immunol. 2009 May;46(8-9):1830-8
references.pmid: 19233475
references.citation: Cell. 2014 Oct 9;159(2):333-45
references.pmid: 25284152
references.citation: Nature. 2010 Feb 18;463(7283):963-7
references.pmid: 20164930
references.citation: Cell. 1989 Sep 22;58(6):1035-46
references.pmid: 2476238
references.citation: PLoS Biol. 2010 Sep 14;8(9):null
references.pmid: 20856903
references.citation: PLoS One. 2015 Jul 06;10(7):e0132333
references.pmid: 26147390
references.citation: J Exp Med. 2003 Nov 17;198(10):1463-73
references.pmid: 14610044
references.citation: Nat Immunol. 2003 Aug;4(8):756-64
references.pmid: 12858172
references.citation: Immunity. 2007 Nov;27(5):735-50
references.pmid: 18023370
references.citation: Nature. 2002 Aug 1;418(6897):552-6
references.pmid: 12152083
references.citation: Immunity. 2007 Mar;26(3):357-69
references.pmid: 17368054
references.citation: Immunity. 1998 Jun;8(6):723-32
references.pmid: 9655486
references.citation: Trends Immunol. 2012 Sep;33(9):437-41
references.pmid: 22771139
references.citation: Nat Immunol. 2008 Jun;9(6):658-66
references.pmid: 18469818
references.citation: J Cell Sci. 1997 Mar;110 ( Pt 5):673-9
references.pmid: 9092949
references.citation: Immunol Cell Biol. 2002 Apr;80(2):156-63
references.pmid: 11940116
references.citation: Cell. 1986 Nov 7;47(3):349-57
references.pmid: 3490311
references.citation: Immunity. 2008 Mar;28(3):324-34
references.pmid: 18308592
references.citation: Nat Immunol. 2007 Sep;8(9):975-83
references.pmid: 17694060
references.citation: J Exp Med. 1997 Oct 6;186(7):1149-58
references.pmid: 9314563
references.citation: Cell. 1994 Jan 14;76(1):17-27
references.pmid: 8287475
references.citation: Cell. 2005 Jul 29;122(2):247-60
references.pmid: 16051149
references.citation: Immunol Rev. 2012 Nov;250(1):120-43
references.pmid: 23046126
references.citation: J Immunol. 2010 Oct 15;185(8):4705-13
references.pmid: 20861357
references.citation: Nature. 1993 Aug 19;364(6439):729-32
references.pmid: 8355789
references.citation: J Exp Med. 1991 Jul 1;174(1):219-28
references.pmid: 1829108