Secretory expression of Cap protein of procine circovirus 2 and its immunogenicity

The gene fragment encoding Cap protein of porcine circovirus 2(PCV2) was cloned into the Baculovirus pFastBacⅠtransfer vector with a honeybee melittin signal peptide.The constructed pFastBac-Cap was transformed into Escherichia coli DH10Bac,resulting the recombinant Baculovirus DNA(Bacmid-Cap) which was confirmed by blue-white plaque assay and antibiotic resistance selection.The Bacmid-Cap was then transfected into Sf9 insect cells by the Cellfectin transfection reagent.The recombinant Cap protein was expressed in High Five cells in the serum-free medium.The SDS-PAGE and Western blotting analysis of recombinant protein showed that the protein could be expressed in insect cells and secreted into the culture medium.For the immunogenicity study,the recombinant protein was then inoculated into BALB/c mice and the results showed that the recombinant protein was able to stimulate B cells to produce special antibodies.In conclusions,the recombinant Baculovirus expressing Cap protein of PCV2 were successfully constructed.This study applies a basis for the development of PCV2 subunit vaccine.