Immunogenicity in guinea pigs by IpaD-STxB recombinant protein

Shigellosis is a major global issue of human health. To date، no effective vaccine has been found against Shigella. One of the major virulent factors in Shigella dysenteriae type 1 is Shigella enterotoxin or STx. STxB has immunogenic، adjuvant، or carrier properties. Vaccine candidate antigens can be coupled with this adjuvant for production of an appropriate vaccine. IpaD has a key role in invasion، virulence، and infection by Shigella. In this study، the gene sequences of STXB and ipaD were obtained from gene bank and corresponding genes were prepared as synthetic construct and then transferred to E. coli BL21DE3. By PCR amplification and enzymatic digestion، protein expression levels were assessed. Its protein expression was confirmed by Western blot technique. After extraction by affinity chromatography، the recombinant protein was injected four times to guinea pigs. The pigs were، then، challenged by Shigella felexneri 2a and active toxin of E. coli O157: H7. The results showed that groups of guinea pigs challenged with 28×LD50 of toxin completely survived. Furthermore، guinea pigs were challenged by inducing Shigella felexneri 2a in their eyes. The results showed that the control pigs got cataracts، whereas the immune pigs were in health. The findings of this study suggest that this recombinant protein is a good candidate for production of a recombinant vaccine against Shigella family.