Structure-Guided Immunoinformatics for the Rational Design of a Multi-Epitope Vaccine Against Batai Orthobunyavirus.

Background/Objectives: Batai orthobunyavirus (BATV) is an emerging mosquito-borne zoonotic pathogen for which no licensed vaccine is currently available. The viral envelope glycoprotein plays an important role in viral attachment and host immune recognition, making it a potential target for rational vaccine design. Methods: In this study, an immunoinformatics-based framework was used to design and evaluate a multi-epitope vaccine candidate targeting the BATV envelope glycoprotein. Selected B-cell, cytotoxic T-lymphocyte (CTL), and helper T-lymphocyte (HTL) epitopes were assembled using appropriate linkers and a human β-defensin adjuvant. Population coverage and in silico immune simulations were conducted to evaluate the potential breadth and magnitude of immune response. Results: The final vaccine construct demonstrated favorable physicochemical characteristics, high predicted antigenicity (0.7959), and non-allergenic properties while maintaining favorable predicted structural characteristics and broad predicted population coverage (99.92%). Structural docking revealed a stable interaction between the vaccine construct and human TLR4, with a weighted docking score of -1194.8, suggesting favorable molecular recognition and receptor engagement. Normal Mode Analysis further supported the structural stability and conformational integrity of the vaccine receptor complex. Immune simulation predicted robust primary and secondary immune responses characterized by elevated IgM and IgG antibody production, sustained memory cell formation, and strong IFN-γ and IL-2 responses, indicating the potential to elicit balanced humoral and cellular immunity. Conclusions: This study presents a structurally optimized and validated multiepitope vaccine candidate against the emerging Batai orthobunyavirus. These computational findings identified a promising vaccine candidate for further investigation; however, its immunogenicity, safety, and protective efficacy before further vaccine development can be considered.