[Expression of porcine interferon-gamma and its safe antiviral assay]

In order to ensure the biosafety of the IFN-gamma antiviral activity assay, we used a replication-deficient VSV carrying GFP as an interferon sensitive indicator virus (VSVdeltaG*G). The antiviral activities of porcine IFN-gamma expressed in Escherichia coli and in baculovirus on MDBK cells were assessed. The results showed that the antiviral activity of porcine IFN-gamma expressed in baculovirus could reach 10(5) IU/mL, while the porcine IFN-gamma expressed in E. coli showed some antiviral activity (32 IU/mL) after refolding. The results of the VSVdeltaG*G-based antiviral assay were almost identical to that of the VSV*GFP-based assay, suggesting it is highly feasible to use VSVdeltaG*G as a substitute for VSV*GFP, making assays for IFN-gamma antiviral activity safer and more accurate.