Interferons (IFNs) are natural proteins produced by wide variety of cells in response to viral infection or other biological inducers, and they execute diversified functions as antiviral defense, immune activation and cell growth regulation. Four genes encoding porcine interferons (PoIFN), PoIFN-alpha, PoIFN-gamma, PoIFN-alphagamma or PolFN-omega, were cloned and sequenced. The four types of porcine interferon genes were subcloned into the pET-His vector, and expressed in Escherichia coli Rosetta (DE3). The recombinant products were purified and renaturalized from inclusion bodies to obtain a native state of well biological activity. Antiviral activity assays for porcine interferons were performed and evaluated by standard procedures in following cell/virus test systems: Marc-145/PRRSV, Marc-145/VSV, PK-15/VSV, Vero/VSV or MDBK/VSV. The data showed that both PoIFN-alpha and PoIFN-alpagamma demonstrated significant antiviral activities, and the titer of them against PRRSV was up to 10(8) U/mg. PoIFN-gamma had approximately half or one-thirds antiviral activity of PoIFN-alpha. PoIFN-omega showed inconspicuous antiviral activity.
Amino Acid Sequence ; Animals ; Antiviral Agents ; pharmacology ; Cloning, Molecular ; Escherichia coli ; genetics ; metabolism ; Interferon Type I ; biosynthesis ; genetics ; pharmacology ; Interferon-gamma ; biosynthesis ; genetics ; pharmacology ; Molecular Sequence Data ; Porcine respiratory and reproductive syndrome virus ; drug effects ; Recombinant Proteins ; biosynthesis ; genetics ; pharmacology ; Swine