Expression of Recombinant Human Follicle-Stimulating Hormone in CHO Cells

Objective To express recombinant human follicle-stimulating hormone(FSH) in CHO cells.Methods Recombinant plasmid pcDNA5 / dhfr / FSH containing the α and β subunits of FSH linked at gene level with internal ribosome entry site(IRES) sequence was constructed under the control of a single CMV promoter and transfected to CHO cells,based on which a recombinant CHO cell strain for stable expression was screened and analyzed for growth and expression of target protein.Results Restriction analysis and sequencing proved that recombinant plasmid pcDNA5 / dhfr / FSH was constructed correctly,with which the positive cloning rate of transfected CHO cells was 80.65%.A recombinant CHO cell strain D5 was obtained by MTX pressure and cloning screening.The expression level of FSH in D5 cell strain in serum-free fed-batch culture in shake-flask was 2.5 IU / ml,which increased by more than 2 times and reached 6 IU / ml in bioreactor with controllable culture parameters.Conclusion A method for expression of heterodimeric glycoprotein in CHO cells was developed.The obtained recombinant CHO cells were suitable for serum-free and large-scale cultures,with which the target protein was highly expressed in bioreactor,and the expression level might be further increased by optimization of culture condition.