Screening and identification of eiptope mimic peptide of monoclonal antibodies against vibrio cholerae O1 serotype Ogawa

Abstract:

Objective：To obtain the mimic peptide highly binding to cholerae O1 serotype Ogawa by using purified IXiao3G6 McAb to biospan in phage display random 7 peptides library and to establish the basement for further research of the mimic peptide vaccine of vibrio cholerae. Methods：Purified IXiao3G6 McAb was used to biospan in phage display random 7 peptides library and mimic epitopes were acquired after 3 rounds of biospanning. ‘Double-antibodysandwich’ ELISA and specific inhibition test were used to analyze the combining ability and specificity of the obtained phage short peptide and the IXiao3G6 McAb. DNA sequence analysis was used to an－alyze the sequence of the positive clones and the related bioinformatic tools were used to analyze the alignments. Results：After three rounds of biospanning，the positive phages were enriched effectively. Twenty-two phage clones were positive of the 25 phage clones se－lected randomly by ‘double-antibodysandwich’ ELISA. DNA sequence analysis showed that the amino acid sequences of 20 positive clones were identical completely，which was identified as APAIPAS. Alignment analysis showed no homologous known sequence. Spe－cific inhibition test showed that the lipopolysaccharide（LPS） of cholerae O1 serotype Ogawa could inhibit the binding of the positive clones with IXiao3G6 McAb and the inhibitory intensity was enhanced by increment of the content of LPS，while the LPS of control bacteria did not show the corresponding inhibitory effect. These results further demonstrated phage display peptide could be mimetic to the antigen epitope of the LPS of cholerae O1 serotype Ogawa. Conclusions：Mimic peptide mimesis to the antigen epitope of the LPS of cholerae O1 serotype Ogawa serves as the basement for development of the mimic peptide vaccine of vibrio cholerae.