The role of I-Ag7 beta chain in peptide binding and antigen recognition by T cells.
We examine here how the beta chain of the class II MHC molecule I-Ag7 influences T cell recognition. Three sets of T cell clones were identified. The first set recognizes peptides bound to I-Ag7, I-Ad and I-Ag7 mutant in which the allele-specific residues His and Ser at position 56 and 57 were changed to the Pro at residue 56 and to non-polymorphic Asp at residue 57. The second set responds to the antigen presented only by I-Ag7 and does not recognize the peptides bound to the other class II molecules. The third set is also specific for I-Ag7 as a result of the poor binding of the peptide to I-Ad and the mutant I-Ag7. These results indicate that positions 56 and 57 of the I-Ag7 class II MHC beta chain play a role in both T cell recognition of the MHC-peptide complex and peptide binding to MHC. These two different functions may be involved in I-Ag7-restricted beta cell antigen recognition by diabetogenic T cell clones.
Kanagawa
O
O
Department of Pathology, Washington University School of Medicine, St Louis, MO 63110, USA.
Shimizu
J
J
Unanue
E R
ER
D000818:Animals; D000941:Antigens / Q000378:metabolism; D002999:Clone Cells; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000737:chemistry* / Q000378:metabolism; D006825:Hybridomas; D007114:Immunization; D007515:Islets of Langerhans / Q000276:immunology; D008213:Lymphocyte Activation; D051379:Mice; D016688:Mice, Inbred NOD; D010455:Peptides / Q000276:immunology / Q000378:metabolism; D011485:Protein Binding; D013601:T-Lymphocytes / Q000276:immunology*
D000941:Antigens; D000949:Histocompatibility Antigens Class II; D010455:Peptides