Objective      To screen a high-affinity peptide specific for vasoactive intestinal peptide receptor VPAC1 using phage display peptide library

and to identify the specificity and affinity of the selected peptide.        Methods       A eukaryotic cell line stably expressing VPAC1 was established

four-round subtractive panning using phage display peptide library was conducted

and then forty phage clones were randomly picked out for sequencing. The positive phage clones were identified using cellular ELISA

and exogenous dodecapeptide was determined and synthesized. In vitro competitive binding analysis and flow cytometry were performed to evaluate the binding specificity and affinity of target dodecapeptide.       Results       VPAC1 was stably expressed on transfected CHO-K1/VPAC1 cells. A significant enrichment was obtained through four rounds of panning

and fifteen different peptide sequences were identified from forty clones. Seven phage clones had specific and high affinity binding with positive cells through cellular ELISA analysis. The positive phage clones bound to CHO-K1/VPAC1 through candidate peptide VP1

and VP1 could specifically bind to VPAC1.       Conclusion       A high-affinity dodecapeptide specific for VPAC1 is obtained using phage display peptide library.