1. The solvent-inaccessible Cys67 residue of HLA-B27 contributes to T cell recognition of HLA-B27/peptide complexes.
- Author
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Appel H, Kuon W, Kuhne M, Hülsmeyer M, Kollnberger S, Kuhlmann S, Weiss E, Zeitz M, Wucherpfennig K, Bowness P, and Sieper J
- Subjects
- Aggrecans, Amino Acid Substitution genetics, Amino Acid Substitution immunology, Animals, Cell Line, Cells, Cultured, Cysteine genetics, Epitopes, T-Lymphocyte immunology, Epitopes, T-Lymphocyte metabolism, Extracellular Matrix Proteins administration & dosage, Extracellular Matrix Proteins immunology, Extracellular Matrix Proteins metabolism, Flow Cytometry, HLA-B27 Antigen genetics, Herpesvirus 4, Human immunology, Humans, Immunodominant Epitopes immunology, Immunodominant Epitopes metabolism, Lectins, C-Type, Mice, Mice, Inbred BALB C, Mice, Transgenic, Peptide Fragments administration & dosage, Protein Binding genetics, Protein Binding immunology, Protein Folding, Proteoglycans administration & dosage, Proteoglycans immunology, Proteoglycans metabolism, Receptors, Immunologic genetics, Serine genetics, Solvents chemistry, Transfection, Antigen Presentation genetics, CD8-Positive T-Lymphocytes immunology, CD8-Positive T-Lymphocytes metabolism, Cysteine chemistry, HLA-B27 Antigen immunology, HLA-B27 Antigen metabolism, Peptide Fragments immunology, Peptide Fragments metabolism
- Abstract
Crystallographic studies have suggested that the cysteine at position 67 (Cys(67)) in the B pocket of the MHC molecule HLA-B*2705 is of importance for peptide binding, and biophysical studies have documented altered thermodynamic stability of the molecule when Cys(67) was mutated to serine (Ser(67)). In this study, we used HLA-B27.Cys(67) and HLA-B27.Ser(67) tetramers with defined T cell epitopes to determine the contribution of this polymorphic, solvent-inaccessible MHC residue to T cell recognition. We generated these HLA-B27 tetramers using immunodominant viral peptides with high binding affinity to HLA-B27 and cartilage-derived peptides with lower affinity. We demonstrate that the yield of refolding of HLA-B27.Ser(67) molecules was higher than for HLA-B27.Cys(67) molecules and strongly dependent on the affinity of the peptide. T cell recognition did not differ between HLA-B27.Cys(67) and HLA.B27.Ser(67) tetramers for the viral peptides that were investigated. However, an aggrecan peptide-specific T cell line derived from an HLA-B27 transgenic BALB/c mouse bound significantly stronger to the HLA-B27.Cys(67) tetramer than to the HLA-B27.Ser(67) tetramer. Modeling studies of the molecular structure suggest the loss of a SH ... pi hydrogen bond with the Cys-->Ser substitution in the HLA-B27 H chain which reduces the stability of the HLA-B27/peptide complex. These results demonstrate that a solvent-inaccessible residue in the B pocket of HLA-B27 can affect TCR binding in a peptide-dependent fashion.
- Published
- 2004
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