Immunoinformatic approach for rational identification of immunogenic peptides against host entry and/or exit monkeypox proteins and potential multi-epitope vaccine construction.

COVID-19 has intensified humanity's concern about the emergence of new pandemics. Since 2018, epidemic outbreaks of the Monkeypox virus (MPXV) have become worrisome. In June 2022, the World Health Organization (WHO) declared the disease a global health emergency, with 14,500 cases reported by the Center for Disease Control and Prevention (CDC) in 60 countries. Therefore, the development of a vaccine based on the current virus genome is of paramount importance in combating new cases. In view of this, we hypothesized the obtainment of rational immunogenic peptides predicted from proteins responsible for the entry of the MPXV into the host (A17L, A26L/A30L, A33R, H2R, L1R), exit (A27L, A35R, A36R, C19L), and both (B5R). To achieve this, we aligned the genome sequencing data of MPXV isolated from an infected individual in the United States in June 2022 (ON674051.1) with the reference genome dated 2001 (NC_003310.1) for conservation analysis. Immune Epitope Database (IEDB) server was used for the identification and characterization of epitopes of each protein related to MHC-I or MHC-II interaction and recognition by B cell receptors, resulting in 138 epitopes for A17L, 233 for A28L, 48 for A33R, 77 for H2R, 77 for L1R, 270 for A27L, 72 for A35R, A36R, 148 for C19L, and 276 for B5R. These epitopes were tested in silico for antigenicity, physicochemical properties, and allergenicity, resulting in a total of 51, 40, 10, 34, 38, 57, 25, 7, 47, and 53 epitopes, respectively. Additionally, to select an epitope with the highest promiscuity of binding to MHCs and BCR simultaneously, all epitopes of each protein were aligned, and the most repetitive and antigenic regions were identified. By classifying the results, we obtained 23 epitopes from the entry proteins, 16 epitopes from the exit proteins, and 7 epitopes from both. Subsequently, one epitope from each protein was selected and fused to construct a chimeric protein that has potential as a multi-epitope vaccine. The constructed vaccine was then analyzed for its physicochemical, antigenic, and allergenic properties. Protein modeling, molecular dynamics, and molecular docking were also performed on TLR-2, TLR-4, and TLR-8 receptors, followed by in silico immune simulation of the vaccine. Finally, the results indicate an effective, stable, and safe vaccine that can be further tested, especially in vitro and in vivo, to validate the findings demonstrated in silico.