Expression of recombinant porcine interferon-λ3 in E.coli and the anti-virus activity analysis

Porcine IFN-λ3(λ3-interferon)gene was amplified by using RT-PCR from ST cells stimulated with poly(I∶C)and subcloned into pET-32 aexpression vector,transformed into host bacteria Rosetta gami B.The IFN-λ3gene contained a ORF of 588 bp in length,which shared87.6% sequence identities with that of sheep IFN-λ3(XM_004015683).Phylogenetic analysis showed that the porcine IFN-λ3was species-specific.SDS-PAGE analysis and Western-blot analysis showed that recombinant porcine IFN-λ3was about 32 000 expressed by IPTG-induction,and existed in inclusion bodies.Porcine IFN-λ3was purified by Ni-NTA affinity chromatography.After refolding,IFN-λ3possessed a anti-vesicular stomatitis virus activity at 2×103 U/mg.