Expression and immunological characterization of the OmpA protein from Vibrio parahaemolyticus strain SH112

Abstract:

[Objective] OmpA protein (VPA1186) of Vibrio parahaemolyticus SH112 stain plays an important role in pathogenesis and can be a potential vaccine candidate against V. parahaemolyticus infection. We expressed and to immunologically characterized OmpA protein from strain SH112. [Methods] The ompA gene from strain SH112 was amplified by PCR method and cloned into express vector. The coding protein was analyzed according to the sequencing analysis. The protein was expressed in Escherichia coli BL21(DE3). The mouse anti-OmpA antiserums were generated by immunization of ICR mice with the recombinant protein purified by Ni-NTA. The immunogenicity and the specificity of OmpA were detected by Western blotting analysis. The vaccine protective efficacy of OmpA was verified by animal challenge experiment. [Results] The 40 kDa recombinant protein His-OmpA was successfully expressed. ELISA result shows that the titer of antiserum was above 1:50000. Moreover, Western blotting results reveals the antiserum reacted not only specifically with the purified His-OmpA protein but also with outer membrane proteins and whole-cell proteins of V. parahaemolyticus, suggesting that the expressed protein remained the immunogenicity of original OmpA protein. In addition, Western blotting result reveals that the antiserum reacted specifically with about 36 kDa proteins from four other V. parahaemolyticus strains with major serotypes in domestic, but not reacted with other non-V. parahaemolyticus strains, suggesting the antiserums have a high specificity and the protein maybe a common protective antigen in different V. parahaemolyticus isolates. We further showed that OmpA conferred protective effect as about 35% of mice survived V. parahaemolyticus infection. [Conclusion] Our findings indicate that OmpA protein could play important roles in development of diagnostic test and may serve as candidate vaccine against V. parahaemolyticus infection.