Codon and Signal Peptide Optimization to Enhance Therapeutic Antibody Production from CHO Cells

A simple and rapid method for reproducible transient expression experiments to quickly identify the best conditions before the development of a stable CHO cell line is described, using adalimumab as a model antibody. Firstly, the signal peptide (SP) is optimized using different in silico programs, of which those having a D score of more than 0.85 will be selected. A list of useful SPs is provided. Next, guidelines for selecting the codon optimization algorithm is provided based on a CAI value of more than 0.95. After that, the codon optimized genes of the heavy chain (HC) and light chain (LC) of an antibody with different SPs are engineered into an expression vector and the two recombinant plasmids are co-transfected into a CHO cell line of interest. The antibody titer, specific productivity (Qp), and viable cell density (VCD) are then checked by ELISA and flow cytometry analysis. The best SP pairs can then be used for the development of stable CHO cell lines.