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[Selecting the phage displaying tetrodotoxin mimic epitope by phage random peptide library].

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.