Two Amino Acids on the α Helical Region of the α1 Domain Form Multiple Epitopes Recognized by HLA-Bw52 Specific Human Cytotoxic T Cell

Abstract

We have previously demonstrated that amino acid substitutions of Asn →Glu at position 63 and Ser→Phe at position 67 are only differences between HLA-B51 and HLA-Bw52 (Hayashi 1989). As these substitutions are located on the helical region of the α1 domain, both T and B cells are suspected to discriminte one from the other. Several studies (Ajitkumar 1988, Hogan 1988) using mutant HLA or H-2 antigens recently demonstrated that the repertoire of allogeneic CTL was extremely large. We focused on only two residues of the helical region on the α1 domain, in which the amino acid substitutions between HLA-B51 and Bw52 are found, to analyze the allorecognition of CTL. We attempted to generate HLA-Bw52 specific CTL clones and constructed the chimeric molecules between HLA-B51 and Bw52 to investigate the epitope formation of alloantigen which T cells recognize and the repertoire of allogeneic CTL against only two amino acid substitutions.