An FcγRIIa-binding peptide that mimics the interaction between FcγRIIa and IgG

Abstract

A disulphide-constrained peptide that binds to the low affinity Fc receptor, FcγRIIa (CD32) has been identified and its structure solved by NMR. Linear (7-mer and 12-mer) and disulphide-constrained (7-mer) phage display peptide libraries were panned on recombinant soluble FcγRIIa genetically fused to HSA (HSA-FcγRIIa). Peptides were isolated only from the constrained peptide library and these contained the consensus sequence, CWPGWxxC. Phage clones displaying variants of the peptide consensus sequence bound to FcγRIIa and the strongest binding clone C7C1 (CWPGWDLNC) competed with IgG for binding to FcγRIIa and was inhibited from binding to FcγRIIa by the FcγRIIa-blocking antibody, IV.3, sugg..