Peptide inhibitors of human IL-5 selected from phage random peptide library
Objective To find related polypeptides which could bind to interleukin (IL)-5 and inhibit the biologcial funtion of IL-5. Methods The recombiant human IL-5 was biotinylated with NSH-LC-Biotin, and used to react with random peptide library displaying 7 amino acids fused on protein Ⅲ of M13 phage for three rounds biopanning. The selected clons were assayed by ELISA. The displayed polypeptides of positive phage clones with high affinity and synthesized polypeptides were tested for their effects on IL-5-mediated eosinophils survival. Results Nine positive phage clones with high affinity were obtained after 3 rounds of biopanning, 3 of which could inhibit the effect of IL-5-mediated eosinophils survival. The two of most effective displayed-polypeptide were synthesized, and one of them presented the inhibition effect on IL-5 funtion in vitro by inducing apoptosis. Conclusion Potential polypeptides against IL-5 could be selected from phage display peptide library, which provide the basis for novel anti-IL-5 agents.