Abstract: In order to acquire efficient expression and production of biologically active duck IFN-α, the mature protein gene of duck IFN-α was amplified from pMD18T-MaIFN-α. The fragment was linked to the prokaryotic expression vector pET-32a to construct the recombinant expression plasmids pET-32a（+）-MaIFN-α, and then converted into E.coli BL21 cells. The fusion protein was induced to express in the change temperature condition. SDS-PAGE and western blotting analysis were used to examine the fusion protein. After purified by Ni²⁺ resin column, the activity of the expression product was determined. The results showed that the recombinant pET-32a（+）-MaIFN-α expressed a soluble protein after being induced by IPTG. Western blotting analysis showed the fusion protein had expected antigenicity. The activity of the expressed duck IFN-α detected by inhibiting cytopathic effect was about 8×10⁴ U/mL. The activity detected by the Real-time PCR showed that the expressed duck IFN-α had a strong inhibition of NDV replication in DEF. This indicated that the expressed duck IFN-α was verified to be of high antiviral activity.

Key words: Mallard, IFN-α, Soluble expression , Activity analysis