Immunoinformatics-guided design of a multi-epitope vaccine targeting the envelopment polyprotein of oropouche virus

Oropouche virus is an emerging and neglected arbovirus of growing public health concern in Latin America, with recent epidemiological surveillance reporting 832 confirmed cases in 2023 and 5,913 cases during early 2024 in Brazil, predominantly in the Amazon region. Despite its increasing spread, no licensed vaccines or antiviral therapies are currently available. In this study, we aimed to design and computationally evaluate a multi-epitope vaccine candidate targeting the OROV envelopment polyprotein using integrated immunoinformatics, molecular modeling, and immune simulation approaches. The complete polyprotein sequence was analyzed to identify antigenic, non-allergenic, and non-toxic cytotoxic and helper T-cell epitopes. Selected epitopes were assembled into a chimeric construct incorporating an adjuvant, suitable linkers, and a PADRE sequence to enhance immune recognition. Physicochemical properties, tertiary structure, receptor binding, dynamic stability, and immune response potential were comprehensively evaluated in silico. The final vaccine construct comprised 241 amino acids and demonstrated favorable stability with instability index score of 24.95, hydrophilicity with GRAVY score of - 0.241, and with an estimated global population coverage of 94.07%. Molecular docking revealed favourable binding affinity to TLR4 with a binding energy of - 1067.1, while molecular dynamics simulations showed structural stability, with an average RMSD of 0.40 nm and limited fluctuations. Immune simulations predicted rapid antigen clearance, robust Th1-polarized responses characterized by strong IFN-γ and IL-2 production, sustained IgG responses, and expansion of memory B and T cells. Overall, these findings indicate that the proposed multi-epitope vaccine construct is stable, immunogenic, and capable of inducing broad immune responses, providing a strong rationale for experimental validation and future vaccine development against Oropouche virus.