Fig.5 The one-step growth curve of 2PCV2b, 2PCV2-6M, 2PCV2d and 2PCV2d-6M) produced by transfection of PK-15 cells with DNA clones. The infectious titers were determined by IFA according to the Student’st tests methods.
In conclusion, this study demonstrated that the 6th aa mutations within the PCV2 Rep protein are important for enhanced PCV2d replication ability in PK-15 cells, having no effect on the replication capability of PCV2b. Based on these findings, with other genes that contributes to changes the virulence and pathogenicity, it is possible to find an inactivated vaccine candidate strain of PCV2 with high viral titer to protect pigs from porcine circovirus diseases.