A library of 2 ×107 random octapeptides was constructed by use of phagemid-based monovalent phage display system. The randomly synthesized degenerated oligodeoxyribonucleotides （oligos ） were fused to the truncated g Ⅲ （p230-p403）. Sequence analysis of 11 randomly chosen clones suggested that the degenerated inserts and its deduced amino acid （aa） sequences are randomly distributed. The library was used to select binding peptides to the monoclonal antibody （mAb） 9E10

which recognizes a continuous decapeptide epi- tope of denatured human c-myc protein. After four to five rounds of panning

most of the eluted clones could bind to 9E10. Sequence analysis of the selected positive clones indicated that the binding sequences could fall into two classes

one class （clone 1） shares a consensus motif

ISE x x L

with c-myc decapeptide; and the sequences of the other class are entirely different. The binding of both classes to 9E10 could be specifically inhibited by free c-myc decapeptide. The immunogenicity of the phage peptide was further investigated by construction of multivalent displayed phage peptides and immunization of animals with or without adjuvant. ELISA and competitive ELISA showed that anti-serum from both mice and rabbit immunized with either clone could bind to the original antigen

c-myc decapeptide. These results denote that in spite of the dissimilarity of the selected peptides with c-myc decapeptide

they are capable of inducing similar immune respones in vivo

thus actually mimicking the antigen epitope.