Abstract:

Deoxynivalenol (DON) mimotope, designated as CDON, is a mimicking epitope (CMRPWLQ) screened from a phagedisplayed
random peptide library. In order to replace DON conjugated toxin with non-toxic recombinant protein in ELISA, two
novel expression vectors, which were designated as plasmid pGEX-CDON and phagemid pC89S4-CDON, were used to produce
GST-CDON and pⅧ-CDON fusion proteins in E. coli. After purification, both GST-CDON and pⅧ-CDON fusion proteins showed
good reactogenicity with an anti-DON antibody in a competitive inhibition ELISA test. When GST-CDON was used as coating
antigen, the linear range of the competitive inhibition ELISA was 31–500 ng/mL with an IC50 value of 194 ng/mL, and spiked
recoveries were 54.1%–65.4%, with coefficient of variation of 6.28%–13.37%. The detection limit was 31 ng/mL. Upon using pⅧ-
CDON as coating protein, the linear range of the competitive inhibition ELISA was 15–500 ng/mL with an IC50 value of 94 ng/mL,
and spiked recoveries were 81.7%–89.0%, with coefficient of variation of 3.15%–7.55%. The detection limit was 15 ng/mL.
ELISA analysis and comparison showed that the reactogenicity and specificity of pⅧ-CDON binding to anti-DON antibody
were better than that of GST-CDON fusion protein. Therefore, pⅧ-CDON is promising for establishing an ELISA without the
application of the toxic mycotoxin conjugate.

Key words: deoxynivalenol, mimotope, plasmid, phagemid