Efficacy of a Commercial PCV2a Vaccine with a Two-Dose Regimen Against PCV2d

Figures

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  Figure 1. Antibody responses to vaccination: Mean post-vaccination porcine circovirus 2-specific IgG titers by ELISA. X-axis—days post-vaccination, Y-axis—antibody titer calculated as the last dilution showing an optical density higher than the positive cut off. Solid line—unvaccinated group, dashed line—vaccinated group, * p < 0.05.

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  Figure 2. Rescue of recombinant virus culture from transfected PK-15 cells. Representative images of an immunofluorescent assay (IFA) of PK-15 cells transfected with the respective PCV2 infectious clones. Green nuclear florescence typical of PCV2 replication was detected using a PCV2-specific monoclonal antibody. (A) PCV2a; (B) PCV2b and (C) PCV2c.

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  Figure 3. Virus neutralization assay: Virus neutralizing antibodies measured by a fluorescent focus neutralization assay using days post vaccination 35 pre-challenge sera. X-axis—virus genotype used in the assay, light slanted lines—unvaccinated group, dark horizontal lines—vaccinated group Y-axis—mean % reduction in fluorescent foci compared to the untreated virus culture. * p < 0.05.

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  Figure 4. Post-challenge viral loads in pigs: Mean log10 genome copies/mL of serum as measured by a PCV2-specific qPCR using DPC 0, 10 and 21 sera. X-axis—days post-challenge, Y-axis—log10 genome copies/mL, light slanted lines—unvaccinated group, dark horizontal lines—vaccinated group, * p < 0.05.

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  Figure 5. Post-challenge clinical observations: (A) Mean average daily weight gain during the 21-day post challenge observation period. X-axis—groups, Y-axis—average daily weight gain in grams. (B) Mean body temperatures during the 21-day post challenge observation period. X-axis—days post-challenge, Y-axis—temperature in °F, solid line—unvaccinated group, dashed line—vaccinated group. No significant differences were found between the groups.