Preparation and Characterization of SA-hIL2 Fusion Protein

Objective:To prepare and characterize streptavidin-tagged human interleukin-2(SA-hIL2)fusion protein.Methods:pET24a-6His-SA-hIL2 plasmid was constructed and expressed in BL 21(DE3)host bacteria to generate fusion protein.The recombinant fusion protein SA-hIL2 was purified through the Ni-NTA affinity chromatography,and then refolded.The efficiency of surface modification of the fusion protein on the biotinylated B16.F10 tumor cells was evaluated by a flow cytometer.CCK-8 method was used to determine the proliferating effect of SA-hIL2 fusion protein on human peripheral-blood lymphocyte(PBL)cells stimulated by PHA.Results:The recombinant SA-hIL2 fusion protein was highly expressed in BL21(DE3)at up to 20% of total bacterial proteins.The fusion protein SA-hIL2 exhibited the bi-functionality:proliferation promoting activity of hIL-2 on PBL cells,and SA-mediated high-affinity binding to the biotinylated surface of B16.F10 cells with about 95% surface modification efficiency.Conclusion:SA-IL2 bi-functional fusion protein was generated,which will make feasible the development of hIL2-surtface-modified cancer cell vaccine.