The Prokaryotic Expression and Its Antiviral Activity of Porcine Interferon-γ

For constructing recombinant expression vector pET-mPoIFN-γ,the mature peptide gene for porcine interferon-γ(mPoIFN-γ) was amplified by RT-PCR depending on the template of total RNA which was isolated from the peripheral blood lymphocyte of ConA-stimulated Landrace swine,and then subcloned into pET-28a vector.After detection by PCR,restriction enzyme digestion and sequencing,the recombinant plasmid was transformed into Escherichia coli BL21(DE3) and inducted by IPTG.The SDS-PAGE analysis and Western blot results showed that the porcine interferon-γ was highly expressed with immune activity and the expressed product was about 20.5kDa,was existed mainly in inclusion body.The recombinant product was purified and renaturalized from inclusion body to obtain the protein with biological activity.Antiviral activity assay for PoIFN-γ was performed and evaluated by standard procedures in H-PRRSV/Marc-145(virus/cell) test system.The results showed that the titer of PoIFN-γ against H-PRRSV was 7.68×103 U/mg.The research laid a foundation for the function investigation of PoIFN-γ.