Field evaluation of novel plant-derived porcine circovirus type 2 vaccine related to subclinical infection

BackgroundThe objective of this field trial was to evaluate the efficacy of a new plant-based porcine circovirus type 2a (PCV2a) vaccine. This vaccine was a recombinant capsid subunit PCV2a vaccine based on the Nicotiana benthamiana expression system.MethodsThree farms were selected for the study based on their history of subclinical PCV2 infection. A total of 40 18-day-old pigs were randomly allocated to either vaccinated or unvaccinated groups (20 pigs per group; 10 = male and 10 = female). Pigs received a 2.0-mL dose of the plant-based PCV2a vaccine intramuscularly at 21 days of age in accordance with the manufacturer's recommendations, whereas unvaccinated pigs were administered a single dose of phosphate buffered-saline at the same age.ResultsVaccination had a positive effect on pig growth performance compared to that of unvaccinated pigs on all three of the farms. Vaccination of pigs with a plant-based PCV2a vaccine induced high levels of neutralizing antibodies titres against PCV2d and PCV2d-specific interferon-& gamma; secreting cells which resulted in the reduction of PCV2d viral load and reduced lymphoid lesions severity.ConclusionsThe results of this field trial demonstrated cross-protection of PCV2d by a plant-based PCV2a vaccine and a positive effect of pig growth performance with vaccination. The novel plant-based (Nicotiana benthamiana) PCV2a vaccine provides cross-protection of PCV2d and a positive effect on pig's growth performance under field conditions.image