Generation and immunogenicity of a recombinant pseudorabies virus expressing cap protein of porcine circovirus type 2

Porcine circovirus type 2 (PCV2) is associated with post-weaning multisystemic wasting syndrome (PMWS), which is an important economical disease affecting the pig industry worldwide. In order to develop an effective vaccine for PMWS, a recombinant pseudorabies virus (PRV) was generated and tested in piglets in this study. The PCV2 open reading frame 2 (ORF2) gene was inserted into pIECMV plasmid and co-transfected with PRV Tk−/gE−/LacZ+ genome into IBRS-2 cells to generate a recombinant Tk−/gE−/ORF2+ virus. The expression of PCV2 ORF2 gene in the recombinant virus was confirmed by Western blotting and indirect immunofluorescence assay (IFA). Four-week-old piglets were immunized by the recombinant virus, and the immunogenicity of PRV Tk−/gE−/ORF2+ was tested by PRV-enzyme-linked immunosorbent assay (ELISA), PRV neutralizing assay, ORF2-ELISA and ORF2 specific lymphocyte proliferation response. PRV Tk−/gE−/ORF2+ elicited significant humoral immune responses to both PRV and PCV2, and the PCV2-specific lymphocyte proliferation response could be detected on day 49 of this experiment. These findings suggest that the recombinant PRV Tk−/gE−/ORF2+ may be a potential vaccine against both PCV2 and PRV.