Abstract: The objective of this work is to optimize the conditions while recombinant plasmids encoding Fc-fusion protein and antibody transfect into CHO-S cells for improving the transfection efficiency and subsequently increasing the expression of exogenous proteins. The target genes were transfected into the CHO-S cells with Amaxa Nucleofector-II and the transfection conditions were screened from the 3 perspectives of electrotransfection programs,plasmid dosage and cell dosage. The optimized conditions for the Fc-fusion protein were found to be electroporation program U-030,plasmid dosage 20 μg/well,and cell dosage 1×10⁷cells/well;while the optimized conditions for the antibody were electroporation program U-024,plasmid dosage 15 μg/well,and cell dosage 1×10⁷ cells/well. It was found that the transfection efficiency for the gene of the antibody was higher than that for the gene of Fc-fusion protein,which was also demonstrated by the ratio of positive clone analyzed with Clone Pix. This study provides data on electrotransfection of genes for antibody and Fc-fusion protein to CHO-S cells,also indicating that the importance of optimizing the electroporation conditions for different cell lines and target genes for obtaining stable and high-yield producing cell lines.

Key words: fusion protein, antibody, electrotransfection, transfection efficiency