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.