Designing an efficient multi-epitope vaccine against Campylobacter jejuni using immunoinformatics and reverse vaccinology approach

Campylobacterjejuni causes acute diarrhea as a leading cause of morbidity and mortality in children especially in the developing countries of Asia and Africa. C.jejuni has been identified as a member of the priority pathogens category due to the sudden emergence of multidrug-resistant isolates. Therefore, it is important to develop a protective vaccine against this pathogen. In the present study, the Reverse vaccinology approach was used to identify vaccine targets from the proteome of diarrheagenic C. jejuni strain NCTC11168 for the development of chimeric vaccine candidates against C. jejuni. Pathogen proteins that have adhesin like properties and role in virulence but not present in the human host were selected for the design of a multi-epitope vaccine. MHC class I & II and B-cell epitopes present in the selected vaccine target proteins were screened using different immunoinformatics tools. The commonly predicted epitopes from their corresponding different servers were selected and further shortlisted based on their immunogenicity, antigenicity, and toxicity analysis. Shortlisted peptides were joined by GPGPG linkers to design a multi-epitope vaccine construct. Immune-modulating adjuvant monophosphoryl lipid sequence was added with the vaccine construct's N terminal using EAAAK linkers to enhance the immunogenicity. The designed vaccine construct was evaluated by antigenicity, allergenicity, solubility, and physicochemical analysis using various bioinformatics tools. A three-dimensional model of vaccine construct was modeled by the Phyre2 server and refinement by the GalaxyRefine tool. Constructed model quality was validated by the ProSA-web error-detection tool and the Ramachandran plot. After that vaccine model was docked with TLR-4 protein and complex stability confirmed by molecular dynamics simulation studies. Finally, In-silico cloning of vaccine constructs into a vector was performed to ensuring its effective expression in the microbial system.