title: Highly efficient peptide binding and T cell activation by MHC class II molecules of CIITA-transfected cells.
abstract: Expression of MHC class II, DM and Ii genes is controlled by the transactivator CIITA, a mediator of the activation of these genes by IFN-gamma. Surprisingly, MHC class II molecules expressed on CIITA transfectants behave very differently from those expressed at the same level on IFN-gamma-induced cells in terms of peptide binding and peptide-specific T cell activation. MHC class II-positive CIITA transfectants exhibit an unusually high capacity for binding exogenous peptides, with a higher percentage of DR molecules occupied by a given peptide and are much more efficient at peptide-specific, HLA-DR-restricted activation of T lymphocytes. This unexpected phenotype reflects the antigen processing defect observed in CIITA transfectants. It suggests novel strategies for the use of CIITA-transformed cells in peptide-based immunization.
authors.affiliation: L. Jeantet Laboratory of Molecular Genetics, Department of Genetics and Microbiology, University of Geneva Medical School, Switzerland.
authors.forename: E
authors.initials: E
authors.lastname: Martinez-Soria
authors.forename: C A
authors.initials: CA
authors.lastname: Siegrist
authors.forename: B
authors.initials: B
authors.lastname: Mach
mesh_terms: D017951:Antigen Presentation; D002461:Cell Line, Transformed; D002478:Cells, Cultured; D005786:Gene Expression Regulation; D005802:Genes, MHC Class II; D006684:HLA-DR Antigens / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000235:genetics* / Q000276:immunology*; D006801:Humans; D008213:Lymphocyte Activation; D009687:Nuclear Proteins; D011485:Protein Binding; D013601:T-Lymphocytes / Q000276:immunology*; D015534:Trans-Activators / Q000235:genetics*; D014162:Transfection
chemical_list: D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II; C083728:MHC class II transactivator protein; D009687:Nuclear Proteins; D015534:Trans-Activators