Immunogenicity of the Recombinant Chimeric Protein STXB-Intimin- Escc Against Pathogenicity of Enterohemorrhagic Escherichia coli O157:H7

Enterohemorrhagic Escherichia coli serotype O157:H7 is an important pathogen in humans and animals that causes a number of gastrointestinal complications, including the hemorrhagic colitis and in acute cases, the hemolytic uremic syndrome (HUS). Considering the risks of antibiotic treatments, vaccines provide a promising way to prevent this infection. The aim of this study was to evaluate the immunogenicity of chimeric antigen STXB-EscC-Intimin (SEI) against E.coli O157: H7. A recombinant chimeric protein expression was induced by IPTG in E.coli BL21 DE3 and evaluated by SDS-PAGE. The recombinant protein was purified by Ni-NTA affinity chromatography. The purified protein was confirmed by ELISA using anti Shiga toxin specific antibodies. Immunization was performed in mice with pure protein and the antibody titer was determined by ELISA. Bacterial shedding and mortality in mice were examined. Statistical analysis was performed by Duncan tests and t-test with SPSS software. Expression of a protein with a molecular weight of 74/5 kDa was observed in SDS-PAGE. The minimum amount of detected antigen with anti Shiga-like poultry antibody using ELISA method was 0.156 μg. Bacterial shedding in immunized mice was reduced to 102 cfu/ml, and 80% of the immunized mice survived the bacterial injection of 10LD50. The results showed that the recombinant chimeric protein could be a suitable vaccine candidate against E. coli O157: H7.