Recombinant Expression and Antibody Cross-reaction of the Outer Membrane Protein VP1008 and Ferric Vibrioferrin Receptor of Vibrio parahaemolyticus

Objective: The study of V. parahaemolyticus specific surface antigens is of importance to develop immunoassays of immune detection. The immunogenicity study of V. parahaemolyticus differential outer membrane protein (VP1008) and ferric vibrioferrin receptor (pvuA) has not been revealed. Methods: The target genes were amplified from the genome DNA and the recombinant plasmids pET-28a(+) were respectively constructed and transformed into E. coli BL21. The two recombinant proteins were both induced by Isopropyl-β-D-Thiogalactoside (IPTG). After purified by a NI-NTA column, the purified recombinant proteins were immunized to the BALB/c mice. The cross-reaction of the polyclone antibodies (pAb) with different isolates of V. parahaemolyticus and other Vibrio species was studied by enzyme-linked immunosorbent assay (ELISA) and immunoblotting. Results: The recombinant protein VP1008 and Vibrio ferritin receptor were expressed as inclusion bodies, the pAb both strongly reacted to the corresponding recombinant protein (>1000 K), reacted with 7 strains of V. parahaemolyticus (4.5~13.5 K), and basically did not react with 10 strains of Vibrio, the cross-reaction with Enterobacteriaceae strains was related with the residual proteins of E. coli during the purification steps. The pAb also both reacted with the target protein in the cell lysates of the V. parahaemolyticus strains. Comparatively, the pAb against VP1008 had a higher antibody titer and immunogenicity. Conclusion: The pAb against the recombinant Omp VP1008 recognized the V. parahaemolyticus strains with higher titer, which laid the foundation for preparing a new immunoassay against V. parahaemolyticus.