MUTANTS OF HUMAN ??2-MICROGLOBULIN MAP AN IMMUNODOMINANT EPITOPE WITHIN THE THREE-STRANDED ??-PLEATED SHEET1,2
- 27 August 1997
- journal article
- immunobiology
- Published by Wolters Kluwer Health in Transplantation
- Vol. 64 (4) , 640-645
- https://doi.org/10.1097/00007890-199708270-00016
Abstract
Genetically engineered structural variants of human β2-microglobulin (β2m) were produced by sequence exchange with mouse β2m for the purpose of examining species-specific antigenic determinant expression. For aggregate mapping, mouse and human β2m, which differ by 30% in their primary sequence of 99 amino acids, were prepared as chimeric (human X mouse) molecules and expressed in the FO-1 β2m-null human melanoma cell line. A chimera containing residues 1-69 from human β2m (and residues 70-99 from mouse β2m) induced expression of the epitopes defined by the anti-β2m monoclonal antibodies (mAb) BBM.1, NAMB-1, and L368; the reverse chimera did not, although HLA class I heavy chain was evident on the cell surface as determined with the TP25.99 mAb. For fine dissection of the epitopes defined by these mAbs, site-directed mutants of β2m were prepared by replacement of individual amino acids in human β2m with the dimorphic residue from mouse β2m. Substitutions were made at each divergent residue between positions 1 and 66 and, as controls for COOH-terminal modification, a series of residues between positions 75 and 94. Replacement of amino acids 38, 44, and 45, but not 16 other dimorphic residues in the linear stretch from residue 1 to residue 66, resulted in the loss of, or gross reduction in, binding by mAbs BBM.1 and NAMB-1. A reduction in binding was also observed for mAb L368. These data provide strong evidence that the antigenic epitopes defined by these mAb map to a region including S3 and its adjacent intra-β-strand turn of the three-stranded β-pleated sheet of β2m. The mapping of these epitopes is consistent with their accessibility in the assembled major histocompatibility complex class I molecule and indicates that the region from amino acid 38 to 45 is an important structural feature in the “foreignness” of human and mouse β2m.Keywords
This publication has 18 references indexed in Scilit:
- MHC CLASS I HEAVY CHAIN-DEPENDENT EXPRESSION OF DISCONTINUOUS ANTIGENIC EPITOPES ON β2-MICROGLOBULINb IS INDUCIBLE WITH PEPTIDE-LIGANDTransplantation, 1995
- Changes in Rheumatoid Factor and Monoclonal IgG Antibody Specificity after Site-Specific Mutations in Antigenic Region of β2-MicroglobulinClinical Immunology and Immunopathology, 1994
- The three-dimensional structure of H-2Db at 2.4 Å resolution: Implications for antigen-determinant selectionCell, 1994
- Assembly-dependent expression of antigenic epitopes by ?2-microglobulinbImmunogenetics, 1993
- Crystal Structures of Two Viral Peptides in Complex with Murine MHC Class I H-2K bScience, 1992
- Structure of the human class I histocompatibility antigen, HLA-A2Nature, 1987
- Altered structure of HLA class I heavy chains associated with mouse beta-2 microglobulinImmunogenetics, 1985
- Characterization of a monoclonal anti‐β2‐microglobulin antibody and its use in the genetic and biochemical analysis of major histocompatibility antigensEuropean Journal of Immunology, 1979
- THE SMALL SUBUNIT OF HL-A ANTIGENS IS ß2-MICROGLOBULINThe Journal of Experimental Medicine, 1973
- Papain-Solubilized HL-A Antigens from Cultured Human Lymphocytes Contain Two Peptide FragmentsProceedings of the National Academy of Sciences, 1973