Computational Analysis to identify conserved immunogenic regions containing multiple epitopes of Orthohantavirus puumalaense

Background: Emerging zoonotic Orthohantavirus Puumalaense (PUUV) causes nephropathia epidemica, a mild form of Hemorrhagic Fever with Renal Syndrome (HFRS). The virus's natural host is bank vole (Myodes glareolus) and is prevalent in Europe and Russia. Search for immunogenic candidates is vital for developing vaccines and diagnostic tools for orthohantavirus infections. Materials & Methods: The FASTA files containing distinct PUUV nucleocapsid (N) protein sequences were obtained from NCBI after eliminating all duplicate sequences. CD8+ and CD4+ T cell epitopes were predicted using NetMHCpan-4.1 and NetMHCiipan, respectively, whilst ABCpred was used to define B-cell epitopes in the conserved part of N protein. Also, the screening of peptides for antigenicity, allergenicity, and toxicity was performed using Vaxijen v2.0, AllerTOP v2.0, and ToxinPred, respectively. Peptide-HLA coverage estimation and identifying globally effective peptide vaccine candidates were accomplished by utilising IEDB population analysis. HPEPdock server-based molecular docking was used to assess the interactions between HLA and epitopes/peptides. Results: Three conserved peptides that contain epitopes recognised by CD8+ and CD4+ T cells and B cells epitopes were identified. These identified peptides were devoid of exhibiting allergenic and autoimmune responses. Additionally, examining population coverage utilising the IEDB database indicated that the selected peptides showed an average population coverage exceeding 90% across five continents. Molecular docking results revealed that root mean square deviation (RMSD) values of the peptides/epitopes were comparable to those of native peptides (peptides that are bound to HLA in the PDB database) for 10 HLA class I alleles and 10 class II alleles. These data demonstrated a strong affinity between epitopes and HLA molecules. Discussion: Our selected peptides were not reported when the IEDB database, which provides information about experimentally validated epitopes, was cross-checked. Partial fragments of these peptides were reported to induce T and B cell response, indicating the immunogenic capability of these peptides. Conclusion: Three peptides containing immunodominant epitopes were identified based on epitope prediction algorithms, IEDB population coverage and molecular docking. These analyses support the immunogenic potential of selected peptides, which needs to be validated in different in vitro and in vivo experimental systems.