Analyzing the various fusions for ctxB, ipaD and stxB genes of Shigella dysenteriae and Vibrio cholera by Bioinformatics tools

Shigella dysenteriae type 1 is a major cause of diarrhea in humans and also Cholera is a potentially fatal bacterial infection that causes severe diarrhea and dehydration. Thus، producing a vaccine against these bacteria seems to be very useful. The best methods for making a vaccine against these two diseases is enterotoxin B subunit in both of them، which names StxB (for Shigella dysenteriae type 1) and CtxB (for Vibrio cholera). These two parts connect the toxic subunit (subunit A) to cell surface receptors of these two toxins in the intestinal epithelium. Shigella IpaD proteins can also be a good target to produce a vaccine against Shigella. IpaD is required for pore formation، bacterial invasion، and virulence. IpaD is responsible for insertion of IpaB/IpaC pores into target cell membranes. Consequently، producing antibodies against IpaD can prevent shigella from making pores in cells and after immune response against them antibodies can prevent the entry of the toxin into the cells. CtxB is highly effective mucosal adjuvant triggering strong protective immunity to unrelated antigens and can be used to prevent or treat inflammatory diseases. Therefore، fusion of these three genes to produce vaccine has two main important benefits: i) by using of adjuvant properties of CtxB، immunization against IpaD and StxB would increase; ii) this vaccine could be effective against both of these bacteria. The study compares all the possible combinations of binary and ternary proteins with various properties by the use of bioinformatics software such as Modeller، ProtParam and psipred and identifies CtxB-StxB-IpaD as the best possible combination.