Exploratory Evaluation of Peptide-Based Immunization Targeting Fusion Glycoprotein-Derived Epitopes of Nipah Virus in Murine Model

Abstract

<bold>Background:</bold> Nipah virus (NiV), a zoonotic paramyxovirus with high case fatality and pandemic potential, remains without a licensed vaccine for humans to date. Although there has been progress in vaccine development, it remains limited, and peptide vaccines have rarely been validated in vivo. <bold>Methods:</bold> Here, we report the rational antigen selection, synthesis, and preliminary immunogenicity evaluation of NiV fusion glycoprotein (NiV-F)-derived linear peptides as vaccine candidates. Candidate epitopes were identified by in silico, and a total of 18 B- and T-cell epitope-derived peptides were shortlisted for synthesis and antigenicity validation by ELISA. <bold>Results:</bold> Antigenicity evaluation showed that 9 of the synthesized peptides have A(450nm) of over 1 (8 from the F11 group, A(450nm): 1.13-3.6; 1 from the F18 group, A(450nm): 1.51), with the peptide constructs F11-3 (A(450nm): 3.5) and F11-4 (A(450nm): 3.6) showing the highest antigenicity. Interestingly, peptides from F11 with amidation increased antibody binding (F11-4-NH2, A(450nm): 3.05; F11-4-9mer-1-NH2, A(450nm): 0.87). The lead peptide candidates, F11-3 and F11-4, were subsequently used for the immunization experiment, and mouse sera were assessed against their homologous peptide antigens or recombinant NiV-F protein. ELISA result showed detectable antibody reactivity against their homologous antigen for the intramuscular (IM) F11-3 vaccinated group (A(450nm): 0.30 +/- 0.35), whereas increased binding was observed for both IM-administered F11-3 (A(450nm): 1.62 +/- 0.97) and F11-4 (A(450nm): 2.0 +/- 0.77) against NiV-F protein, albeit without statistical significance compared to the negative control (NC, p > 0.05), and were markedly lower compared to mice immunized with NiV-F recombinant protein (PC, p < 0.01), underscoring the need for further optimization procedures. <bold>Conclusions:</bold> Collectively, these results support an exploratory antigen discovery and prioritization framework for NiV-F-derived peptide candidates and provide a foundation for future studies aimed at optimizing immunogenicity and evaluating protective relevance in appropriate preclinical models.