Identification of HLA-DR9 (DRB1∗0901)-binding peptide motifs using a phage fUSE5 random peptide library

• Published in: Human immunology 1996-02, Vol.45 (2), p.131-136
• Main Authors: Fujisao, Shoji, Matsushita, Sho, Nishi, Tohru, Nishimura, Yasuharu
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Clone Cells; Coliphages - genetics; Coliphages - immunology; Gene Library; HLA-DR Antigens - biosynthesis; HLA-DR Antigens - isolation & purification; HLA-DR Antigens - metabolism; HLA-DR Serological Subtypes; Humans; Molecular Sequence Data; Peptide Fragments - biosynthesis; Peptide Fragments - isolation & purification; Peptide Fragments - metabolism; Protein Binding - immunology
• ISSN: 0198-8859; 1879-1166
• DOI: 10.1016/0198-8859(95)00169-7

We identified HLA-DRB1 ∗0901-binding peptides by affinity-based selection of a phage random peptide library using the biotinylated DR9 complex. Analogue peptides with single amino acid residue substitutions of a DR9 binder revealed that two major anchors (WxxS, where x is any amino acid) play an essential role in binding to DR9. Determination of the binding affinity of synthetic wild-type-based analogue peptides showed that substituting W to F or L, and S to A, V, or F allow high affinity binding with DR9. Collectively, DR9-binding peptide motifs identified in this study are characteristic in that (a) only two anchors of the NH 2-terminal half of binding peptides play important roles in binding, and (b) small neutral hydrophilic Ser is allowed as the second anchor for high-affinity binding, unlike the other DR-binding motifs heretofore reported. The implications of our results are discussed in light of the HLA-DR9-associated susceptibility to juvenile-onset myasthenia gravis and systemic lupus erythematosus with antiphospholipid syndrome, in particular, T-cell responses to au-toantigens.