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Animal Virus Infections Studies / Animal Disease Management and Epidemiology · Journal article
The Journal of Immunology · July 28, 2026
Early or partial results. Treat as a signal, not a conclusion.
This is an early-stage experimental vaccine study in cesarean-derived, colostrum-deprived pigs challenged with PCV3. The ORF2-based prototype vaccine prevented viral shedding in fecal and nasal swabs and reduced viremia, but produced no overt clinical benefit because sham-vaccinated animals also remained clinically asymptomatic. The findings characterize immune mechanisms rather than establish clinical efficacy.
Experimental controlled challenge study with four randomized treatment groups. Cesarean-derived, colostrum-deprived pigs aged 8 weeks at vaccination; setting not specified.. Intervention: 150 µg recombinant PCV3 ORF2 protein formulated with 18% (v/v) Emulsigen D, administered intramuscularly with boost and subsequent challenge with 133.33 µg PCV3 via IM or IN route. Compared with: Sham-vaccinated, sham-challenged controls; sham-vaccinated, PCV3-challenged controls; vaccinated, sham-challenged controls. n = 24.
IM challenge produced earlier and higher viral loads than IN challenge; vaccination delayed and reduced but did not prevent viremia Vaccination prevented viral shedding in fecal and nasal swabs Vaccinated pigs developed PCV3-specific IgG prior to challenge, with higher post-challenge levels following IN exposure
Safety was not reported in the material analysed. Check the source before drawing any conclusion about harm.
The absence of clinical disease in both vaccinated and sham-vaccinated challenged animals limits interpretation of vaccine benefit for disease prevention in this model. The immunological data suggest the vaccine modulates immune responses and prevents viral shedding, but clinical significance in natural infection or conventional piglets remains unknown.
Small single-site controlled animal study with surrogate immunological endpoints and no clinical disease observed; provides mechanistic insight into PCV3 vaccine response but lacks power and clinical outcome data needed for efficacy claims.
As stated by the source record.
Quoted from the source exactly as published.
The absence of clinical disease in both vaccinated and sham-vaccinated challenged animals limits interpretation of vaccine benefit for disease prevention in this model. The immunological data suggest the vaccine modulates immune responses and prevents viral shedding, but clinical significance in natural infection or conventional piglets remains unknown.
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Abstract Introduction PCV3 is a pathogenic member of the family Circoviridae infecting pigs. PCV3-associated disease has been linked to reproductive failure, wasting syndromes, and multisystemic inflammation, although subclinical infections are often reported. Despite global detection, limited experimental studies have hindered comprehensive characterization of PCV3 pathogenesis and host immune responses. Methods Eight-week-old CDCD pigs were intramuscularly vaccinated and boosted with 150 µg of recombinant PCV3 ORF2 protein formulated with 18% (v/v) Emulsigen D and subsequently challenged with 133.33 µg PCV3 via intramuscular (IM) or intranasal (IN) routes. Treatment groups (n = 6/group) included vaccinated or sham-vaccinated pigs subjected to homologous sham or PCV3 challenge by either route. Serum, oral fluids, fecal (FS) and nasal swabs (NS), and PBMCs were collected longitudinally and analyzed by RT-qPCR, ELISA, and flow cytometry. Results No clinical signs were observed throughout the study. Inoculation route and vaccination status significantly influenced the temporal dynamics of PCV3 viremia and viral shedding. IM challenge resulted in earlier, higher viral loads compared with IN challenge, which showed a gradual increase over time. Vaccination prevented viral shedding in FS and NS but only delayed and reduced viremia. Vaccinated pigs developed PCV3-specific IgG prior to challenge, with higher post-challenge levels observed following IN exposure. In contrast, sham-vaccinated challenged pigs exhibited impaired humoral responses. Immune cell profiling revealed a robust early IFN-γ response that was attenuated in vaccinated groups and followed by an increase in regulatory T cells. Conclusion Subclinical PCV3 infection was associated with prolonged viremia. Characterization of a prototype ORF2-based vaccine demonstrated enhanced IgG response, modulation of inflammatory cytokine responses, and prevention of viral shedding, providing insight into PCV3 immunobiology and informing future vaccine development strategies. Funding Source n/a Topic Categories Veterinary and Comparative Immunology (VET)
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