In silico Design of a New Multi-epitope Polypeptide against Vibrio cholerae O1 biovar ElTor

In this study, due to the importance of cholera as a water-borne infection, a new and appropriate multi-epitope polypeptide was designed against Vibrio cholerae O1 biovar ElTor using the reverse vaccinology method and immunoinformatic implements.

After identification of all ORFs of chromosome 1 bacterium, their outer membrane and secretory proteins were determined. Then, by removing the signal peptide and transmembrane domain, non-toxic, non-allergenic, and antigenic proteins were selected from the proteins of the previous step. Finally, high-score epitopes of the final antigenic proteins were identified using several specific software. To design the multi-epitope polypeptide, selected epitopes, and an appropriate adjuvant were connected using a flexible linker.

To validate the biochemical properties of the designed polypeptide, we implemented a range of servers to evaluate the biochemical and physicochemical properties of the designed polypeptide. Subsequently, we performed a molecular binding study to investigate the interaction of the designed polypeptide with the MHC I and MHC II molecules. The designed polypeptide contained 277 amino acids with a half-life of approximately 30 hours in mammalian cells. The results confirmed that this designed polypeptide not only has sufficient antigenic properties without toxicity and allergenicity but also has a good affinity for binding to MHC molecules.

After synthesis and appropriate immunological tests, the designed polypeptide can be considered as a new candidate vaccine against Vibrio cholera to prevent the spread of infection.