In silico analysis of VP2 protein from infectious bursal disease virus isolate UPM1432/2019: structural dynamics and epitope prediction.

Infectious Bursal Disease Virus (IBDV) remains a significant threat to global poultry health due to its immunosuppressive effects and high mutation rate, which challenge existing vaccine strategies. This study presents a comprehensive computational analysis of the VP2 protein from Malaysian IBDV isolate UPM1432/2019 to elucidate its structural stability and antigenic potential. Phylogenetic analysis revealed evolutionary divergence among VP2 sequences, while physicochemical profiling demonstrated the protein's high thermostability (aliphatic index: 98.77) and cellular stability (instability index: 17.55). Molecular dynamics simulations at 20 °C, 40 °C, 60 °C, and 80 °C showed progressive destabilization at elevated temperatures, indicated by increased RMSD, reduced hydrogen bonding, and higher solvent accessibility. Epitope prediction identified twelve linear and seven conformational B-cell epitopes, with several conserved, surface-exposed regions demonstrating high antigenicity. The most immunodominant conformational epitope (L168-E181) achieved a high ElliPro score of 0.903, indicating strong immune recognition potential. These findings highlight structurally stable and immunoreactive domains within VP2, offering valuable insights for the development of next-generation, thermostable epitope-based vaccines for effective IBDV control.