Expression of biologically active recombinant equine interferon-γ by two different baculovirus gene expression systems using insect cells and silkworm larvae

The full-length equine interferon-gamma (eIFN-gamma) cDNA, including the secretion signal peptide coding region, was recloned into baculovirus transfer vector pAcYM1. This vector was co-transfected with Autographa californica nuclear polyhedrosis virus DNA or hybrid nuclear polyhedrosis virus DNA into Spodoptera frugiperda cells. The recombinant viruses, named AcEIFN-gamma and HyEIFN-gamma, were then recovered. Recombinant eIFN-gamma (relFN-gamma) was accumulated in the culture fluid of the AcEIFN-gamma or HyEIFN-gamma infected Tricoplusia ni-derived cell line, BTI TN 5BI-4, and hemolymph of HyEIFN-gamma infected silkworm larvae. These re1FN-gamma forms were shown to be 14, 16, 18 and 20 kDa proteins, and glycosylated as confirmed by SDS-PAGE and tunicamycin treatment. Both reIFN-gamma proteins, showed high-level biological activities to vesicular stomatitis virus by cytopathic effect reduction assay, and MHC class II antigen induction on the equine fetal kidney-78 cell line. (C) 2002 Elsevier Science Ltd. All rights reserved.