Protective efficacy of a DNA vaccine encoding capsid protein of porcine circovirus-like virus P1 against porcine circovirus 2 in mice.

The capsid protein is the major immunogenic protein of porcine circovirus 2 (PCV2). The nucleotide sequence of porcine circovirus-like virus P1 shares high homology with open reading frame (ORF) 2 of PCV2, and ORF1 of P1 encodes its structural protein. Mice were vaccinated twice intramuscularly with a plasmid expressing the P1 ORF1 protein (pcDNA3.1(+)-ORF1) at 2-week intervals. All animals vaccinated with pcDNA3.1(+)-ORF1 developed higher specific anti-P1 antibody levels, and had less PCV2 viremia and milder histopathological changes than PCV2-challenged mice in the control group. Our results show that the P1 DNA vaccine elicited immune responses against PCV2 infection in a mouse model.