title: Major histocompatibility complex class I binding glycopeptides for the estimation of 'empty' class I molecules.
abstract: Different forms of major histocompatibility complex (MHC) class I heavy chains are known to be expressed on the cell surface, including molecules which are functionally 'empty'. Direct peptide binding to cells is obvious during sensitization of target cells in vitro for cytotoxic T lymphocyte killing and 'empty' MHC-I molecules are comparatively abundant on TAP-1/2 peptide transporter mutant cells. In the present work we have estimated the fraction of 'empty' MHC class I molecules using glycosylated peptides and cellular staining with carbohydrate specific monoclonal antibodies. Synthetic Db and Kb binding peptides were coupled at different positions with different di- or trisaccharides, using different spacing between the carbohydrate and the peptide backbone. Binding of sugar specific mAbs was compared in ELISA and cellular assays. An optimal Db binding glycopeptide was used for comparative staining with anti-Db and anti-carbohydrate monoclonal antibodies to estimate fractions of 'empty' molecules on different T lymphoid cells. On activated normal T cells, a large fraction of Db molecules were found to be 'empty'. The functional role of such 'empty' MHC class I molecules on T cells is presently unclear. However, on antigen presenting cells they might participate in the antigen presentation process.
authors.affiliation: Microbiology and Tumor Biology Center (MTC), Karolinska Institutet, Stockholm, Sweden.
authors.forename: U M
authors.initials: UM
authors.lastname: Abdel-Motal
authors.forename: L
authors.initials: L
authors.lastname: Berg
authors.forename: M
authors.initials: M
authors.lastname: Bengtsson
authors.forename: J
authors.initials: J
authors.lastname: Dahmén
authors.forename: J
authors.initials: J
authors.lastname: Kihlberg
authors.forename: G
authors.initials: G
authors.lastname: Magnusson
authors.forename: U
authors.initials: U
authors.lastname: Nilsson
authors.forename: M
authors.initials: M
authors.lastname: Jondal
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry; D002460:Cell Line; D004187:Disaccharides / Q000737:chemistry / Q000276:immunology; D005679:G(M3) Ganglioside / Q000031:analogs & derivatives / Q000737:chemistry / Q000276:immunology; D006020:Glycopeptides / Q000138:chemical synthesis / Q000276:immunology*; D006183:H-2 Antigens / Q000737:chemistry* / Q000276:immunology; D064532:Histocompatibility Antigen H-2D; D016399:Lymphoma, T-Cell; D051379:Mice; D008969:Molecular Sequence Data; D011485:Protein Binding / Q000276:immunology; D014281:Trihexosylceramides / Q000737:chemistry / Q000276:immunology; D014407:Tumor Cells, Cultured
chemical_list: D000911:Antibodies, Monoclonal; D004187:Disaccharides; D005679:G(M3) Ganglioside; D006020:Glycopeptides; D006183:H-2 Antigens; C032876:H-2Kb protein, mouse; D064532:Histocompatibility Antigen H-2D; D014281:Trihexosylceramides; C081657:ganglioside GM3 lactam; C032103:4-O-alpha-D-galactopyranosyl-D-galactose; C018549:globotriaosylceramide