has role protective antigen role protective antigen Porcine circovirus 2 protein ORF2 Protegen ID: 659; NCBI Protein GI: 78217439; NCBITaxon: 85708 protein Oliver He Allen Xiang An open reading frame 2 plasmid (pORF2) and the capsid protein (Cap) of PCV2 were used as DNA and subunit vaccines, respectively. In FCM analysis, although pORF2 and Cap alone showed comparable efficacy in eliciting lymphoproliferative responses and Cap-specific CD4(+) T cells, pORF2 was superior to the Cap protein in triggering CD8(+) T cells. Following virus challenge, real-time PCR and histopathological analysis confirmed that only low viral DNA loads and mild microscopic lesions appeared in pORF2-immunized mice [PubMed: 18632956].