Alteration of a non-polymorphic residue in a class II E beta gene eliminates an antibody-defined epitope without affecting T cell recognition.
The interaction between the clonally selected T cell receptor, antigen, and Ia molecule is poorly understood at the molecular level. A cell line bearing an altered E beta k molecule has been examined to provide more information about the relationship between Ia structure and function. The cell line, 2B1, was derived from the TA3 B cell hybridoma through a series of negative and positive immunoselection steps. The 2B1 mutant lacked the binding site recognized by the 17.3.3 monoclonal antibody (mAb) but presented antigen normally to all I-Ek-restricted T cell hybridomas and clones examined. Sequence analysis of the mutant E beta k gene showed a single base transition (G----A) that resulted in an arginine to a histidine substitution at amino acid 49 of the beta 1 domain. This mutation demonstrates that residue 49 is not involved in antigen presentation to T cells but can be involved in B cell recognition (mAb binding).
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000938:Antigen-Presenting Cells / Q000276:immunology; D001483:Base Sequence; D002460:Cell Line; D000939:Epitopes / Q000235:genetics* / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000235:genetics* / Q000276:immunology; D051379:Mice; D008815:Mice, Inbred Strains / Q000235:genetics / Q000276:immunology; D009154:Mutation; D011487:Protein Conformation; D013601:T-Lymphocytes / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000939:Epitopes; D000949:Histocompatibility Antigens Class II; C024138:I-E-antigen