In silico pharmacological evaluation of a multi-epitope vaccine candidate targeting the G1 and G2 glycoproteins of Oropouche virus via TLR3 interaction.

Oropouche virus (OROV) is an emerging arbovirus associated with increasing outbreaks with no approved vaccine and antiviral therapies currently availaible. In this study, an in silico pharmacological approach was employed to design and evaluate a multi-epitope vaccine candidate targeting the G1 glycoprotein of OROV. Antigenicity screening identified G1 as a suitable target, while the nucleocapsid (N) and G2 proteins were excluded due to lower antigenicity and predicted toxicity. Immunoinformatic-based epitope mapping was performed to identify cytotoxic T-lymphocyte (CTL) and helper T-lymphocyte (HTL) epitopes that were further screened for antigenicity, non-allergenicity, non-toxicity, and global population coverage. The shortlisted epitopes were used to develop a vaccine design with linkers and a β-defensin adjuvant. Of the two vaccine candidates, the G1-based vaccine (136 amino acids) demonstrated high antigenicity (0.6653) and safety with favorable physicochemical properties while the G2 protein was excluded from further studies due to its toxicity. Population coverage analysis of the G1 vaccine construct demonstrated 95.58% global coverage for MHC class I and II epitopes. Molecular docking and interaction analysis of the MEV with TLR3 showed favorable ClusPro docking score of - 1043.6 kcal/mol. Molecular dynamics simulations showed minimal fluctuations in RMSD and RMSF, indicating stability of the complex under physiological conditions. Immune simulation predicted robust responses with elevated IgM and IgG levels, increased T-cells, and cytokine production, including IL-2 and IL-6. These findings indicate that the G1-based multi-epitope vaccine is a potential candidate for further experimental validation and may serve as an effective preventive strategy against OROV infection.