Conserved epitope-driven in silico design of a multi-epitope vaccine against the tick-borne wetland virus.
BACKGROUND The tick-borne viruses are primarily transmitted through the bites of infected ticks. Wetland virus (WELV) is a newly identified tick-borne pathogen with no licensed vaccines and limited preventive strategies. METHODS In this study, a reverse vaccinology approach was used to design a multi-epitope vaccine using the conserved regions of key viral proteins of WELV. RESULTS Multiple sequence alignment identified 51, 31, and 5 conserved regions in the RNA-dependent RNA polymerase (R), glycoprotein (G), and nucleocapsid (N) proteins, respectively. The epitope prediction across these regions identified 784 CTL, 933 HTL, and 123 B-cell epitopes, from which antigenic, non-allergenic, and non-toxic candidates were selected for vaccine construction. The final construct was predicted to have favourable antigenicity, solubility, and physicochemical properties. Structural analysis revealed that the construct has a high percentage of random coils (49.02%). Then, the tertiary structure was refined to improve its stereochemical quality, and in the refined structure 96.2% residues were in the most favoured regions. The conformational epitope prediction identified thirteen surface-accessible B-cell epitopes. Molecular docking analysis using HADDOCK showed possible interactions with multiple Toll-like receptors with predicted binding free energies ranging from -13.1 to -15.3 kcal/mol. Codon optimization and in silico cloning were performed to insert the construct into the pET-28a(+) vector. The immune simulation analysis predicted the possibility for inducing effective response, with antibody production, T-cell activation, and long-term immunological memory. CONCLUSION These computational results suggest that the construct has the potential to induce effective immunity against WELV, however further experimental validations in future have to be performed in order to confirm its efficacy against the pathogen.