Specificity of glycopeptide-specific T cells.
We examined the specificity of glycopeptide-specific CD4 T cells following procedures similar to those previously reported by us. The disaccharide galabiose (Gal alpha 1-4Gal) was attached to the middle of the 52-61 peptide of hen egg lysozyme. This peptide is well known to bind to I-Ak molecules. CBA/J mice were immunized and T cell hybridomas were derived from the popliteal lymph node T cells. For this study, we selected hybridomas that recognized galabiose conjugated to 52-61 at residue Ser 56. We demonstrate here that these hybridomas showed specificity for galabiose and not cellobiose (Glc beta 1-4Glc). Peptides containing galabiose at residue 53 did not stimulate the T cell hybridomas and neither did galabiose conjugated to the 34-45 peptide of HEL. Acetylation of the hydroxyl groups of the disaccharide resulted in loss of T cell reactivity. These results need to be contrasted with those in which the T cells were directed to galabiose, attached to the amino terminus of 52-61 or to Ser at residue 53. With these results, the fine specificity of recognition of the disaccharide was not apparent. Our results indicate two sets of glycopeptide-specific T cells. One is probably induced by a conformational change induced by the disaccharide on the peptide bound to class II MHC molecules. The second set contains elements of specificity for both the disaccharide and the peptide.
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Center for Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA.
Elofsson
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M
Kihlberg
J
J
Unanue
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ER
D000595:Amino Acid Sequence; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002240:Carbohydrate Sequence; D002475:Cellobiose / Q000276:immunology; D004187:Disaccharides / Q000276:immunology; D005260:Female; D006020:Glycopeptides / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D006825:Hybridomas / Q000276:immunology; D051379:Mice; D008808:Mice, Inbred CBA; D008969:Molecular Sequence Data; D011487:Protein Conformation
D004187:Disaccharides; D006020:Glycopeptides; D000949:Histocompatibility Antigens Class II; C032103:4-O-alpha-D-galactopyranosyl-D-galactose; D002475:Cellobiose