EXPRESSION OF BIOLOGICALLY ACTIVE RECOMBINANT EQUINE INTERFERON-γ BY TWO DIFFERENT BACULOVIRUS GENE EXPRESSION SYSTEMS USING INSECT CELLS AND SILKWORM LARVAE

Abstract The full-length bovine interferon-γ (bIFN-γ) cDNA, including the secretion signal peptide coding region was recloned into baculovirus transfer vectors pAcYM1 and pBm050. These vectors were co-transfected with Autographa californica nuclear polyhedrosis virus (AcNPV) or Bombyx mori nuclear polyhedrosis virus (BmNPV) DNA into Spodoptera frugiperda cells (SF21AE) and Bombyx mori cells (BmN), respectively. The recombinant viruses, named AcBIFN-γ and BmBIFN-γ, were then recovered. Recombinant bIFN-γ (rbIFN-γ) was accumulated in the culture fluid of AcBIFN-γ-infected Trichoplusia ni cells and BmBIFN-γ-infected silkworm larvae. These rbIFN-γ forms were shown to be glycosylated 20 and 22 kDa proteins as confirmed by SDS-PAGE and tunicamycin treatment. These products were sensitive to cystein proteinase. Both rbIFN-γ proteins, showed high-level biological activities by plaque reduction assay using vesicular stomatitis virus, and MHC class II antigen induction on bovine macrophage cells.