title: The role of polymorphic I-Ak beta chain residues in presentation of a peptide from myelin basic protein.
abstract: Proteins encoded by genes in the MHC are highly polymorphic. For class II proteins the highest level of polymorphism is found in distinct regions of variability, notably in the membrane-distal domains. To investigate the role of such residues in antigen presentation, we have tested cells transfected with wild-type or mutant I-Ak beta chains for their ability to present the NH2-terminal peptide of myelin basic protein to a panel of T cell clones. We were unable to detect a gross effect on peptide binding, in that all of the mutant cell lines presented antigen to at least one of the cloned T cells. However, the results imply that the more NH2-terminal residues, particularly 12 and 14, are involved in peptide interactions. Mutations at these residues presented antigen only at high antigen concentrations. Furthermore, residues of the more COOH-terminal regions appear to determine TCR interactions. Mutations in the predicted alpha-helical regions of the beta chain affected antigen presentation without abolishing peptide binding.
authors: Department of Biological Sciences, Stanford University, California 94305.
authors: C B
authors: CB
authors: Davis
authors: J M
authors: JM
authors: Buerstedde
authors: D J
authors: DJ
authors: McKean
authors: P P
authors: PP
authors: Jones
authors: H O
authors: HO
authors: McDevitt
authors: D C
authors: DC
authors: Wraith
mesh_terms: D000596:Amino Acids / Q000235:genetics; D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology*; D002999:Clone Cells / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000235:genetics*; D008213:Lymphocyte Activation; D051379:Mice; D008805:Mice, Inbred A; D009154:Mutation; D004676:Myelin Basic Protein / Q000235:genetics / Q000276:immunology*; D010446:Peptide Fragments / Q000235:genetics / Q000276:immunology*; D011110:Polymorphism, Genetic; D051381:Rats; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D000596:Amino Acids; D000949:Histocompatibility Antigens Class II; D004676:Myelin Basic Protein; D010446:Peptide Fragments