Abstract: 【Aim】 Bac-to-Bac baculovirus expression system was used to obtain a soluble fusion protein sPDGFRβ/Fc, combining the extracellular domain of PDGFR β chain and the Fc region of human IgG in insect cells Sf9, and the specificity and bioactivity of the recombinant protein are detected. 【Methods】 The gene sPDGFRβ/Fc was cloned into a transfer vector pFastBac to form the recombinant donor plasmid pFastbac-sPDGFRβ/Fc, which was transformed into Escherichia coli DH10Bac. By transposition, sPDGFRβ/Fc gene was integrated into Bacmid, and a recombinant shuttle vector rBacmid-sPDGFRβ/Fc was constructed. Then the rBacmid-sPDGFRβ/Fc recombinant genome DNA was used to transfect Sf9 mediated by lipidbody, and the recombinant baculovirus rBacmid-sPDGFRβ/Fc was obtained, which was further used to infect the serum-free cell Sf9 to express sPDGFRβ/Fc. Then the recombinant protein was purified with Protein A chromatography and analyzed by Western blotting and MTT assay. 【Results】 Western blotting analysis showed a specific band about 97 kDa, consistent with the target protein, 75% pure sPDGFRβ/Fc was obtained by using Protein A chromatography with a yield of 1 μg/mL culture medium, which was confirmed to be able to inhibit PDGF-induced proliferation of Balb/c 3T3 cell. 【Conclusion】 The recombinant protein sPDGFRβ/Fc with activity of inhibiting PDGF-induced cell proliferation can be successfully expressed in insect cell.

Key words: Platelet-derived growth factor receptor (PDGFR), baculovirus expression vector system (BEVS) , insect cell, recombinant protein, MTT assay