Abstract
Vaccination is the most efficacious way to prevent Porcine circovirus 2 (PCV2)-associated diseases. In experimental pig studies, vaccine-induced neutralizing antibodies (NAs) appear to play a major role in protection from PCV2 infection. The immune response to PCV2 vaccination of farmed pigs has not been studied in detail. I hypothesize that NAs target conformational epitope(s) present on the surface of PCV2 particles. Highly purified PCV2 particles were found to expose only conformational but not linear epitopes on their surface. The screening 160 sera from farmed pigs showed that reactivity of sera with PCV2 particles correlated positively with the level of NA titer, suggesting that NAs recognize surface-exposed conformational epitope(s). This finding was supported by depleting antibodies reacting with linear epitopes of PCV2. No significant change was observed in the level of NA titer after antibody depletion. Altogether, these data suggest that NAs target conformational epitope(s) on the surface of PCV2 particles.
