Experimental PCV2d challenge of pigs vaccinated with prototype vaccines containing ORF2 from PCV2a, PCV2b or PCV2d

摘要

This study sought to assess the efficacy of three experimental porcine circovirus type 2 vaccines in a PCV2d/PRRSV co-infection system. Commercially available PCV2 vaccines are all currently based on the PCV2a genotype. In recent years, PCV2d has emerged in the United States and is replacing PCV2b as the dominant genotype of PCV2.1 Experimental studies have demonstrated efficacy against PCV2d by commercial vaccines as well as by an experimental replicon particle vaccine based on PCV2d.2,3To date, vaccines of different genotypes of PCV2, made by the same platform, have not been directly compared against a PCV2d challenge. In this study, subunit vaccines consisting of ORF2 full length capsid protein expressed in a baculovirus expression system were tested. The capsid protein ofPCV2a, PCV2b, and PCV2dwere used as the immunizing protein. The commercially produced product, Circumvent~R PCV G2 was included as a positive control. Pigs were then challenged in a PCV2d/PRRSV co-infection challenge model andefficacy was evaluated.