In silico analysis of chimeric recombinant immunogen against three diarrhea causing bacteria

Shigella and Escherichia belong to the Enterobacteriaceae family which are the cause for most of the diarrheal cases in the world. Shigella can cause bacterial dysenteries and shigellosis. One of the most effective proteins for pathogenesis is invasion plasmid antigen C (IpaC). Other bacteria like Enterotoxogenic (ETEC), Enterohemorrhagic (EHEC), and E.coli can also cause diarrhea and produce intestinal disorders. Colonization factor antigen I (CFA/I), a critical virulence protein for these infections, has two subunits i.e. CfaB and CfaE. EHEC Attachment of bacteria is the main step of infection with intimin playing the key role in this function. This study was designed to elicit protection against the majority of diarrheal pathogens via development of polyvalent vaccine against Shigella, ETEC and EHEC. In silico techniques are as best tools to design new vaccines. For this purpose the immunogenic epitopes of CfaB, IpaC and Intimin were identified through bioinformatic tools and were then selected as major antigens to construct a chimeric protein (CII). The humoral and cellular immunities were analyzed bioinformatically. Prediction of allergens and mapping of IgE epitopes were carried out. The bioinformatic analysis showed each domain was folded separately in fusion structure. CII had many T and B cell epitopes in both linear and three-dimensional structures. This prediction of the chimeric construct had the potential to induce CD4+ and CD8+ immune responses against these pathogens. In addition CII could be accessible to surveillance by the immune system in mouse and human. In conclusion, in silico analysis showed that this chimeric protein can be used as a vaccine against Shigella, ETEC and EHEC simultaneously.