Preparation of CHO cell-derived rhIFN-ω-Fc with improved pharmacokinetics

Interferon-omega (IFN-ω) may be a useful, promising and alternative antiviral agent, in addition to IFN-α-2a and IFN-α-2b. To improve the pharmacokinetics of IFN-ω for clinical use, the recombinant human IFN-ω-Fc fusion protein (rhIFN-ω-Fc) was expressed in a Chinese hamster ovary cell line (CHO-S), due to the longer serum half-life of rhIFN-ω-Fc compared to the native IFN-ω protein, and purified by affinity chromatography. Physicochemical characterization of the purified fusion protein was performed by SDS-PAGE electrophoresis, dot blot analysis and N-terminal amino acid sequence analysis. The results show that rhIFN-ω-Fc was highly expressed at the predicted size and with the N-terminal amino acid sequence. The antiviral activity was determined by the ability of IFNs to inhibit the cytopathic effects (CPEs) of vesicular stomatitis virus (VSV) on the human amnion WISH cells. The rhIFN-ω-Fc expressed in CHO-S cells has a specific activity of 1.6×10(7) IU/mg compared to rhIFN-ω expressed in yeast, which has a specific activity of 7×10(7) IU/mg. Equimolar concentrations of rhFN-ω and rhIFN-ω-Fc were administered to rabbits for pharmacokinetics comparison. The terminal half-life of rhIFN-ω-Fc was 35 times higher than that of rhIFN-ω. Thus, rhIFN-ω-Fc can be used as a prospective antiviral candidate especially for the treatment of chronic viral disease, such as hepatitis C virus (HCV) infection.