Preliminary Immunogenicity Evaluation of an Immunoinformatics-Guided Multi-Epitope mRNA Vaccine Against Porcine Epidemic Diarrhea Virus

Background: Porcine epidemic diarrhea virus (PEDV) remains a major threat to the global swine industry, highlighting the urgent need for safe and effective next-generation vaccines. mRNA vaccines have emerged as a promising platform due to their rapid development and favorable safety profile. Objectives: This study aimed to design and perform the preliminary evaluation of a PEDV multi-epitope mRNA vaccine using an immunoinformatics-guided strategy combined with experimental validation. Methods: Immunoinformatics tools were used to identify B-cell and cytotoxic T lymphocyte (CTL) epitopes from the PEDV spike (S), membrane (M), and nucleocapsid (N) proteins. Selected epitopes were assembled into a multi-epitope antigen (E). mRNA constructs encoding S1, S2, and antigen E were synthesized via in vitro transcription and encapsulated into lipid nanoparticles (LNPs). Expression was evaluated in HEK293T cells, and immunogenicity was assessed in mice measuring antigen-specific antibody responses and cytokine levels following immunization. Results: The mRNA constructs exhibited high structural integrity and efficient intracellular translation. The LNP formulations showed good physicochemical stability and delivery efficiency. Immunization with the antigen E mRNA-LNP formulation induced significantly higher PEDV-specific IgG levels compared with control groups. Elevated cytokine levels further indicated activation of both humoral and cellular immune responses. Conclusions: This study presents a feasible workflow for the development of a PEDV multi-epitope mRNA vaccine. The antigen E construct demonstrated favorable immunogenicity in a mouse model, supporting its potential as a promising construct for further investigation and optimization. Although further studies are required to validate antigen expression at the protein level and to further characterize immune mechanisms, these findings provide preliminary evidence supporting the feasibility of multi-epitope mRNA vaccines for PEDV prevention.