Immunoinformatics-based strategies for developing DNA and mRNA vaccines against monkeypox virus (MPXV)

The monkeypox virus (MPXV) is a newly discovered zoonotic orthopoxvirus that can infect humans and shares similarities with the smallpox virus. With no clinically validated treatment for MPXV infections, it is important to develop a broad-range vaccine that is effective against this disease. This study aimed to design novel multiple-epitope DNA and mRNA vaccines against MXPV using comprehensive immunoinformatics and reverse vaccinology techniques. Eleven MPXV proteins were selected from the UniProt database and assessed for their antigenicity and allergenicity. Proteins exhibiting significant antigenicity and non-allergenic characteristics were examined for the prediction of T-cell and B-cell epitopes. Four MHC-I, eight MHC-II, and six B-cell epitopes were coupled with specific linkers and adjuvant peptide sequences to boost the immunological response to the developed vaccine. The designed vaccines showed antigenic nature with a 0.5936 score and solubility nature with a 0.513 score, and its GRAVY score of 0.147 indicates their hydrophilic nature. Structural validation confirmed the superior tertiary structure of the designed vaccines. Molecular docking studies demonstrated a robust interaction between human TLR-8 and the developed vaccines, with a docking score of -1208.2 kcal/mol, and Moleculae Dynamics (MD) simulations confirmed its stability. The immune simulation results indicated that vaccination strongly stimulated immunity, resulting in high concentrations of IgG and IgM antibodies. Cloning analysis and in silico restriction prediction demonstrated the viability of integrating the developed vaccine into an Escherichia coli (E. coli) expression system. Furthermore, an mRNA vaccine was developed by incorporating a 5' cap, 5' untranslated region (UTR), Kozak sequence, and tissue plasminogen activator (tPA) with the CD40 ligand (CD40L) linked to the selected epitopes using EAAAK linkers. A poly (A) tail, MITD1, and 3' UTR were appended to the 3' end of the construct. The mRNA vaccine design incorporated codon optimization, resulting in a CAI score 0.83 and GC content of 60.46%, indicating efficient vaccine expression within host cells. Analysis of several parameters revealed that the architecture of the synthesized mRNA was stable with MFE: -2170.70 kcal/mol. These outcomes may contribute to the development of an experimental MPXV vaccine with stronger potency and superior safety measures. Additional in vitro and in vivo experiments are required to test the safety and efficacy of these newly developed vaccines.