The ORF5 protein of porcine circovirus type 2 enhances viral replication by dampening type I interferon expression in porcine epithelial cells.

Identifying the functional role of each porcine circovirus type 2 (PCV2) ORF associated with host cell modulation might provide better knowledge about the pathogenesis of postweaning multisystemic wasting syndrome (PMWS). PCV2 ORF5 was recently identified and the functional role of ORF5 during pathogenesis after PCV2 infection is largely unknown. In this study, we used RNA-seq to investigate the functional role of PCV2 ORF5 in PCV2-infected porcine epithelial cells. Our data demonstrates that PCV2 ORF5 could inhibit type I interferon (IFN) expression via transcriptional repression of genes involved in type I IFN production, thus enhancing replication of PCV2 in porcine epithelial cells. Therefore, PCV2 ORF5 might have an inhibitory role against host immune surveillance.