title: Endogenous antigen presentation by autoantigen-transfected Epstein-Barr virus-lymphoblastoid cells: T cell receptor N-region hydrophobicity relates to thyroid antigen recognition.
abstract: Seven human T cell lines from a patient with Graves' disease were raised against endogenously generated human thyroid peroxidase (hTPO) with stimulation indices ranging from 2.1 to 7.6. Clonal expansion within these T cell lines was demonstrated by sequencing multiple bacterial colonies containing RT-PCR-generated fragments derived from the expressed hTcRs. Some lines had more than one human T cell receptor (hTcR) alpha and beta chain mRNAs as judged by RT-PCR. Stopcodons present in several hTcR sequences indicated that only one V alpha and one V beta gene were translated. Both the V alpha/beta gene families and the J alpha/beta gene segments differed amongst the lines and no characteristic recognition sequences were discernable in the CDR3 regions. Using Kyte-Doolittle analysis we found hydrophobic peaks in most N alpha-regions (but not N beta regions) suggesting that hydrophobic interactions may be important in the recognition of hTPO. However, increasing affinity values, as measured by SI, were strongly correlated with decreasing hydrophobicity in the N alpha region (1st order regression, r = -0.93138, p < 0.01). Thus, lower affinity, self-reactive, T cells may be more hydrophobic ('sticky') in their N alpha regions while higher affinity cells may be characterized by TcRs with lower hydrophobicity. These findings demonstrate a substantial role for hydrophobic interactions in hTPO-reactive T cell receptors and further support a role for the TcR alpha chain in the recognition of thyroid autoantigen.
authors.affiliation: Department of Medicine, Mount Sinai School of Medicine, New York, New York, USA.
authors.forename: A
authors.initials: A
authors.lastname: Martin
authors.forename: N
authors.initials: N
authors.lastname: Matsuoka
authors.forename: E S
authors.initials: ES
authors.lastname: Concepcion
authors.forename: T F
authors.initials: TF
authors.lastname: Davies
mesh_terms: D017951:Antigen Presentation; D001324:Autoantigens / Q000276:immunology*; D015139:Blotting, Southern; D002460:Cell Line; D004854:Herpesvirus 4, Human / Q000235:genetics*; D006801:Humans; D007453:Iodide Peroxidase / Q000276:immunology*; D016133:Polymerase Chain Reaction; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000737:chemistry* / Q000235:genetics*; D013601:T-Lymphocytes / Q000276:immunology*; D014162:Transfection
chemical_list: D001324:Autoantigens; D016693:Receptors, Antigen, T-Cell, alpha-beta; D007453:Iodide Peroxidase