Identification by site-directed mutagenesis of amino acid residues contributing to serologic and CTL-defined epitope differences between HLA-A2.1 and HLA-A2.3.
Open Access
- 1 October 1988
- journal article
- research article
- Published by Oxford University Press (OUP) in The Journal of Immunology
- Vol. 141 (7) , 2519-2525
- https://doi.org/10.4049/jimmunol.141.7.2519
Abstract
Site-directed mutagenesis of HLA-A2.1 has been used to identify the amino acid substitutions in HLA-A2.3 that are responsible for the lack of recognition of the latter molecule by the HLA-A2/A28 specific antibody, CR11-351, and by HLA-A2.1 specific CTL. Three genes were constructed that encoded HLA-A2 derivatives containing one of the amino acids known to occur in HLA-A2.3: Thr for Ala149, Glu for Val152, and Trp for Leu156. Three additional genes were constructed that encoded the different possible combinations of two amino acid substitutions at these residues. Finally, a gene encoding all three substitutions and equivalent to HLA-A2.3 was constructed. These genes were transfected into the class I negative, human cell line Hmy2.C1R. Analysis of this panel of cells revealed that recognition by the antibody CR11-351 was completely lost when Thr was substituted for Ala149, whereas substitutions at amino acids 152 and 156, either singly or in combination, had no effect on the binding of this antibody. The epitopes recognized by the allogeneic and xenogeneic HLA-A2.1 specific CTL clones used in this study were all affected by either one or two amino acid substitutions. Of those epitopes sensitive to single amino acid changes, none were affected by the substitution of Thr for Ala149, whereas all of them were affected by at least one of the substitutions of Glu for Val 152 or Trp for Leu156. Overall, amino acid residue 152 exerted a stronger effect on the epitopes recognized by HLA-A2.1 specific CTL than did residue 156. Of those epitopes affected only by multiple amino acid substitutions, double substitutions at residues 149 and 152 or at 152 and 156 resulted in a loss of recognition, whereas a mutant with substitutions at residues 149 and 156 was recognized normally. This reemphasizes the importance of residue 152 and indicates that residue 149 can affect epitope formation in conjunction with another amino acid substitution. These results are discussed in the context of current models for the recognition of alloantigens and in light of the recently published three-dimensional structure of the HLA-A2.1 molecule.This publication has 20 references indexed in Scilit:
- Enhancer-dependent expression of human kappa immunoglobulin genes introduced into mouse pre-B lymphocytes by electroporation.Proceedings of the National Academy of Sciences, 1984
- Recognition by xenogeneic cytotoxic T lymphocytes of cells expressing HLA-A2 or HLA-B7 after DNA-mediated gene transfer.Proceedings of the National Academy of Sciences, 1983
- The monoclonal antibody CR11-351 discriminates HLA-A2 variants identified by T cellsImmunogenetics, 1983
- Isolation and characterization of monoclonal mouse cytotoxic T lymphocytes with specificity for HLA-A,B or -DR alloantigens.The Journal of Immunology, 1982
- Delineation of immunologically and biochemically distinct HLA-A2 antigens.The Journal of Immunology, 1982
- Partial purification and some properties of BB7.2 a cytotoxic monoclonal antibody with specificity for HLA-A2 and a variant of HLA-A28Human Immunology, 1981
- Monoclonal antibodies against two separate alloantigenic sites of HLA-1340Immunogenetics, 1981
- The self determinants recognized by human virus-immune T cells can be distinguished from the serologically defined HLA antigens.The Journal of Immunology, 1980
- Production of monoclonal antibodies to group A erythrocytes, HLA and other human cell surface antigens-new tools for genetic analysisCell, 1978
- DNA sequencing with chain-terminating inhibitorsProceedings of the National Academy of Sciences, 1977