SELECTION OF A PEPTIDE WITH AFFINITY FOR THE TUMOR-ASSOCIATED TAG72 ANTIGEN FROM A PHAGE-DISPLAYED LIBRARY

A hexapeptide phage library was used to select peptides with affinity for the tumor-associated TAG72 antigen. Twenty-one phage clones were s elected after the third round of biopanning. Three phage clones with t he same DNA insert of ARTLRF were found to bind more strongly to the T AG72 antigen than other phage clones and the wild-type phage. A synthe tic decapeptide GAARTLRFGA with two conjunctive amino acid residues of the phage coat protein III on each side of the selected peptide was f ound to bind more strongly to the TAG72 antigen than to other antigens such as the mouse metallothionein. Furthermore, immunohistochemical s tudies revealed that this peptide displayed preferential binding to co lonic adenocarcinomatous cells expressing the TAG72 antigen. Therefore , this anti-TAG72 peptide may be useful in serving as the starting poi nt with regard to further designing peptidomimetics as potential pharm aceuticals. (C) 1996 Academic Press, Inc.