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Animal Virus Infections Studies / Animal Disease Management and Epidemiology · Journal article
The Journal of Immunology · July 28, 2026
Encouraging direction, but not yet definitive.
Oral immunization with maize-expressed PEDV-S1 antigen in weaned pigs reduced clinical diarrhea duration (Vaccine-1) or improved post-challenge growth (Vaccine-2) compared to unvaccinated controls, and modulated mesenteric lymph node T and B cell responses and cytokine kinetics in a pattern consistent with mucosal priming. These findings support proof-of-concept for this plant-based oral vaccine platform but require efficacy confirmation in larger, longer-term swine trials and do not establish safety or immunogenicity in target species (neonatal piglets).
Randomized, controlled four-arm trial in animal model. PEDV-negative weaned pigs, 3 weeks old at enrolment.. Intervention: Maize-expressed PEDV-S1 antigen oral vaccine, prime-boost regimen (dose and timing not specified in abstract).. Compared with: Unvaccinated control group and live-challenge-only group (Challenge 2x).. n = 60.
Vaccine-1 showed shorter diarrhea duration; Vaccine-2 showed mild but longer diarrhea yet greater day-45 body weight than Controls (p≤0.01) and Challenge (2x) animals (p≤0.05). Viral shedding was highest in Controls (p≤0.01), intermediate in vaccinated groups, and lowest in Challenge (2x) pigs after second exposure. Mesenteric lymph nodes showed increased CD4+ T cell activation on day 21 in Challenge (2x) pigs and elevated B cells (CD21+SLA-II-DR+) on day 37 across all antigen-experienced groups.
Safety was not reported in the material analysed. Check the source before drawing any conclusion about harm.
Results suggest maize-expressed PEDV-S1 oral vaccine may reduce disease severity and improve growth in vaccinated weaned pigs upon viral challenge, supporting further development. However, translation to field use in neonatal pigs—the target population for PEDV prevention—requires efficacy and safety studies in that age group.
A controlled animal study of sound design showing clinical benefit (reduced diarrhea, improved growth) and coordinated immune responses, but limited by single-species testing, surrogate endpoints, and absence of efficacy statistics for the primary comparisons.
As stated by the source record.
Quoted from the source exactly as published.
Results suggest maize-expressed PEDV-S1 oral vaccine may reduce disease severity and improve growth in vaccinated weaned pigs upon viral challenge, supporting further development. However, translation to field use in neonatal pigs—the target population for PEDV prevention—requires efficacy and safety studies in that age group.
Graded across the dimensions that decide whether you should act, each from what the source actually supports. There is no single score, and where a dimension was not assessed it says so.
Abstract Introduction Porcine epidemic diarrhea virus (PEDV) is an alphacoronavirus that causes severe enteric disease in swine, leading to high neonatal mortality and growth impairment. Oral vaccines can target gut-associated lymphoid tissue, yet the coordination of mucosal and systemic responses during oral immunization remains poorly characterized. This study assessed a maize-expressed PEDV-S1 oral vaccine by characterizing clinical outcomes, viral shedding and lymphocyte cytokine kinetics following challenge Methods Sixty 3-week-old PEDV-negative pigs were assigned to four groups (n = 15): Control, Vaccine-1, Vaccine-2 (with adjuvant), and Challenge (2x). Vaccine groups received a prime-boost regimen before oral challenge with a non-S INDEL PEDV strain on day 35. Challenge (2x) pigs received two live inoculations. Clinical signs, body weight, and fecal viral RNA were monitored. Necropsies on days 7—45 provided samples for flow cytometry of T, B, γδ-T, NK and regulatory subsets expressing IFN-γ or TNF-α Results Oral vaccination altered disease and immunity. Vaccine-1 pigs showed shorter diarrhea, while Vaccine-2 pigs had mild but longer diarrhea yet greater day-45 body weight than Controls (p 0.01) and Challenge (2x) (p 0.05). Viral shedding was highest in Controls (p 0.01), intermediate in vaccinated pigs and lowest in Challenge (2x) animals after their second exposure. Mesenteric lymph nodes (MLN) profiling showed increased CD4+ T cell activation on day 21 in Challenge (2x) pigs and elevated B cells (CD21+SLA-II-DR+) on day 37 across all antigen-experienced groups. IFN-γ+ CD4+/CD8+ cells were reduced at days 7—21 in antigen-experienced groups, consistent with trafficking from MLN. TNF-α+ subsets remained low whereas γδ-T cells increased from days 21-45 with group-specific patterns. FOXP3+CD25+ T cells remained stable Conclusion Maize-expressed PEDV-S1 oral immunization induced coordinated mucosal and systemic immunity, reduced disease and improved growth supporting its value as a practical tool for swine health Funding Source This project was partially funded through an Iowa State University VPR Seed Grant. Topic Categories Veterinary and Comparative Immunology (VET)
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