A Mutation-Based Reverse Vaccinology Approach Considering Variability in Epitopes to Combat Multi-Strains: A Study Using Glycoprotein of LASV.

Lassa virus (LASV) remains a persistent threat to public health, and to combat this, various therapeutics have been developed, but their effectiveness is limited due to the virus's strain variability. Therefore, mutation-based reverse vaccinology approaches were implemented to formulate an epitope-based vaccine against the LASV, considering the variability in the glycoprotein. The glycoprotein was examined to screen out the B and T cell epitopes and further examined for the immunodominant epitope activity assessment. These epitopes were mapped with the identified position to introduce variability. 2 LBL (Linear B-cell lymphocyte), 21 MHC-I (Major Histocompatibility Complex Class I), and 8 MHC-II potential epitopes were considered for wild and mutated (based on the mutation mapping). The wild and mutated vaccines were separately constructed, which comprise 545 amino acids in length by adjoining B and T cell epitopes via a specific linker, and also an adjuvant, PADRE epitope, 6xHis-Tag, was incorporated to enhance the effectiveness. The formulated vaccine showed acceptable 3D structure quality (most favoured of wild: 91.5% and mutated: 91%) and high population coverage, i.e., 94%. The docking examination of wild and mutated vaccine with toll-like receptor 2 (TLR-2) revealed strong binding affinity, that is, -11.1 and -19.9 kcal/mol, and remarkable stability over 100 ns simulation based on the RMSD, RMSF. The immune simulation and in silico-assisted cloning demonstrated a robust immune response and a remarkable expression in Escherichia coli system based on the GC% (wild; 57.51 and mutated; 57.57) and similar codon adaptive index value, that is, 0.93. The integrated approach will certainly aid in designing a mutation-based epitope-based vaccine that may counter different strains of LASV.