Bioinformatic Design and Analysis of Chimeric Immunogen Against Adherence and Toxicity of Vibrio Cholera

Diarrhea caused by intestinal bacteria is a major cause of mortality, especially in children under the age of five in developing countries. Vaccines can be considered as an important solution to prevent these diseases. Toxin-coregulated pilus (TcpA), OMPW and cholera toxin are the most important virulence factors of vibrio cholera and have immunogenic characteristics. In this study, a recombinant immunogen consisting of TcpA, Outer Membrane Protein OMPW, and cholera toxin B-subunit (CtxB) was designed. This chimeric protein, which contains B-cell epitopes and an adjuvant sequence, can potentially increase the likelihood of developing effective immune responses. To increase the probability expression of the OTC protein, gene codons and various parameters effective in expression were optimized. The thermodynamic analysis of the mRNA structure was performed to verify stability. The third structure of the protein was predicted and the quality of the structures was evaluated. Linear and conformational epitopes were also determined. Protein with the sequence of OTC showed the highest antigenicity index. Codon Adaptaion Index of chimer increased to 0/89. The third predicted structure based on the RaptorX server showed good quality. The thermodynamic analysis of the mRNA structure showed that the predicted structure is stable. Conformational and linear epitopes were observed in all three domain of chimeric protein. The results showed that the protein produced from this structure could act as an immunogen against the binding and toxin function of Vibrio cholera bacteria.