Epitope Screening by Use of a Random Peptide-Displayed Phage Library and Polyclonal Antibody-Coupled Liposomes

Abstract

Linear epitopes of sperm whale myoglobin for a rabbit polyclonal anti-myoglobin antibody were determined from a random-peptide displayed phage library by biopanning using antibody-coupled liposomes (AB-MLVs). Two kinds of positive phages displaying peptides (RNFGADAQ and YDLDIGAD) homological to the myoglobin sequence were obtained after 4 rounds of biopanning. Binding affinities of antibodies, which were fractionated from the anti-myoglobin antibody by specificity to both the peptides, were higher than that of an antibody fraction specific to the peptide that was screened by biopanning using an antibody-coated polystyrene tube (AB-Tube). The epitope identified in this study, N(D)FGADAQ has not been reported as an epitope of the rabbit anti-myoglobin antibody. These results suggest that biopanning using AB-MLVs shows much higher selectivity to recover phages displaying peptides with high affinity and specificity than that using the AB-Tube.