Objective: To screen the positive phage displaying the mimic epitope of tetrodotoxin (TTX) by using phage random peptide display library technology and to establish immunoassay for the detection of tetrodotoxin.
Methods: Monoclonal antibody against TTX was used as a ligand to screen the binding peptide from the Ph. D.-7 peptide library. The library is displayed as a fusion protein with the coat protein III of filamentous phage M13. The positive clones were identified by ELISA. Results After four rounds of panning, 7 positive phages binding to the anti-TTX monoclone antibody were obtained, and through indirect competitive ELISA, 3 positive clones inhibiting TTX were screened. A competitive ELISA was established with phage P4, the linear range of the inhibition is 1-20 ng/ml, R2 = 0.9947, the detecting limit is 1 ng/ml.
Conclusion: The phage display technique can be successfully applied to screen the mimic epitope of tetrodotoxin. The acquired phages may be used as the surrogate of the toxin to establish immunoassay.