Prokaryotic-expressed porcine IFN alpha 1-THY alpha 1 fusion proteins exert IFN and THY activities in vitro

摘要

Combined use of interferon (IFN) and thymosin (THY) holds a stronger antiviral effect than when applied individually because of their coordination and complementary action. In this study, prokaryotic expressed porcine IFN alpha 1 (poIFN alpha 1) or the porcine IFN alpha 1-THY alpha 1 fusion protein coding with the Escherichia coli preferred codon sequences connected by the three different linkers were gained in the unlabeled pRSFDDuet-1 expression systems and purified using the strong anion-exchange chromatography and hydrophobic chromatography (among which, one was digested by thrombin because the cleavage site was included in the linker). Then, the activities of IFN and THY in the fusion protein were detected using the cytopathic effect inhibition assay and 1-cell activity assays. SDS PAGE and western blotting results showed that the poIFN alpha 1 or the three poIFN alpha 1-THY alpha 1 fusion proteins with three different linkers were expressed solubly in E. coll. The poIFN alpha 1 protein and three types of poIFN alpha 1-THY alpha 1 fusion proteins with >90% purity were gained. The poIFN alpha 1-LinkerB-THY alpha 1 fusion protein showed the highest interferon activity compared with the others (P < 0.001), and the poIFN alpha 1-LinkerA-THY alpha 1 fusion protein highest thymosin activity (P < 0.05). In this study, a preliminary experiment was conducted for the expression of the poIFN alpha 1 and THY alpha 1 fusion proteins. (C) 2015 The International Alliance for Biological Standardization. Published by Elsevier Ltd. All rights reserved.