an improved method for recovering the protein expressed by open reading frame 2 from porcine circovirus type 2 is provided . the method generally involves the steps of transfecting recombinant virus containing open reading frame 2 coding sequences into cells contained in growth media , causing the virus to express open reading frame 2 , and recovering the expressed protein in the supernate . this recovery should take place beginning approximately 5 days after infection of the cells in order to permit sufficient quantities of recombinant protein to be expressed and secreted from the cell into the growth media . such methods avoid costly and time - consuming extraction procedures required to separate and recover the recombinant protein from within the cells .