Role of HLA-B5101 binding nonamer peptides in formation of the HLA-Bw4 public epitope

• Published in: International immunology 1996-07, Vol.8 (7), p.1027-1034
• Main Authors: Takamiya, Y, Sakaguchi, T, Miwa, K, Takiguchi, M
• Format: Article
• Language: English
• Subjects: Animals; Antibodies, Monoclonal - chemistry; Biopolymers - immunology; Cell Line; Epitopes - biosynthesis; Epitopes - chemistry; Flow Cytometry; HLA-B Antigens - biosynthesis; HLA-B Antigens - chemistry; HLA-B Antigens - physiology; HLA-B molecules; L Cells (Cell Line); mAb; Mice; NKB1 receptor; Peptides - chemistry; Peptides - immunology; Peptides - physiology; Protein Binding - immunology
• ISSN: 0953-8178; 1460-2377
• DOI: 10.1093/intimm/8.7.1027

HLA-Bw4 is one of two HLA-B public epitopes which are discriminated by specific alloantisera and mAb. It is believed that the residues 77–83 of HLA-B molecules form the Bw4 epitope recognized by specific antibodies. This epitope is also recognized by NKB1 receptors on NK cells. We investigated the role of a peptide bound to HLA-B molecules on the formation of the Bw4 epitope recognized by two HLA-Bw4-speclfic mAb, TÜ109 and TÜ48, which recognized the difference of the Bw4 epitope among HLA-B51, -B52 and -B53. Recognition of the HLA-B*5101–peptide complex by these mAb was examined using a panel of HLA-B*5101 binding nonamer peptides. The sequence of HLA-B*5101 binding peptides has a minimum influence on the binding of TÜ48 mAb to HLA-B*5101 molecules. In contrast, the binding of TÜ109 mAb to HLA-B*5101 molecules was critically influenced by the sequence of a peptide bound to HLA-B*5101 molecules. TÜ109 mAb did not recognize HLA-B*5101 binding peptides carrying small or negatively charged residues at P8. The results were confirmed by a panel of mutant peptides at P8. Taken together, these results indicate that a positively charged or neutralized side chain of P8 is critical for the epitope formation of Bw4 recognized by this mAb.