Interferons (IFNs) are a family of pleiotropic cytokines used for the treatment of various viral infections and cancers.Recombinant IFNs have been used as anti-infectious agents exhibiting a broad range of antiviral and immunomodulatory properties in both human and domestic animals.Escherichia coli is the most extensively used host for the production of recombinant proteins.However,most of the eukaryotic proteins are typically obtained as insoluble,misfolded inclusion bodies that need solubilization and refolding.In this report,recombinant porcine interferon alpha was expressed in Escherichia coli as soluble form,and was purified to homogeneity using essentially two-step chromatographic procedures,i.e.immobilized metal-ion-affinity chromatography and DEAE anion exchange chromatography.The antiviral activity of the final rPoIFNα protein was 1.1x 106 IU/ ml protein,which is comparable with the HuIFNα1 standard.To establish methods and requirements for quality control of rPoIFNα protein,the research of quality control includes biological activity (anti-virus activity),purity (included electrophoresis assay and HPLC assay ),protein content,molecular weight,isoelectric point,test for bacterial endotoxin,Ultraviolet spectroscopy,peptide mapping,N-terminal amino acid sequence.