Expression of Recombinant Proteins IpaD-STxB and Immunogenicity STxB in the Mice

Background and The most common cause of diarrhea is Shigella and no vaccine has been found so far. IpaD and STxB proteins (B subunit of Shiga toxin) play an important role in invasion، infection and pathogenesis caused by Shigella. To evaluate the immunogenicity of each of the proteins IpaD and STxB can using of two animal models mice and guinea pigs and could be determined role of each recombinant protein IpaD-STxB for appropriate vaccine. In this experimental study، the gene sequences of stxB & ipaD were obtained from gene bank and was purchased the synthetic gene. This gene transferred to E. coli BL21DE3 and produced the protein by the bacterium. The level of recombinant protein expression was evaluated and confirmed by techniques of Western bloting. Recombinant proteins were purificated using column chromatography، and were injected into mice four times consecutively. After the second injection (first booster)، a week after each injection، were collected blood samples and was performed ELISA. The results showed that was raised antibody titers against IpaD-STxB protein in the mice. The immunogenicity was evaluated using active toxin E. coli: O157: H7. The challenge results showed that immunized mice could endure 7. 5 times the LD50 Shiga toxin E. coli O157: H7. The protein obtained of the fusion ipaD and stxB genes could protect mice against Shiga toxin. Consequently، STxB proteins were induced immunogenicity in an animal model mice and recombinant protein obtained can be a suitable candidate for the production of recombinant vaccine against Shigella types.