A simple method to determine IgG light chain to heavy chain polypeptide ratios expressed by CHO cells

Objectives To establish a high-throughput method for determination of antibodies intra- and extracellular light chain (LC) to heavy chain (HC) polypeptide ratio as screening parameter during cell line development. Results Chinese Hamster Ovary (CHO) TurboCell pools containing different designed vectors supposed to result in different LC:HC polypeptide ratios were generated by targeted integration. Cell culture supernatants and cell lysates of a fed batch experiment were purified by combined Protein A and anti-kappa affinity batch purification in 96-well format. Capture of all antibodies and their fragments allowed the determination of the intra- and extracellular LC:HC peptide ratios by reduced SDS capillary electrophoresis. Results demonstrate that the method is suitable to show the significant impact of the vector design on the intra- and extracellular LC:HC polypeptide ratios. Conclusion Determination of LC:HC polypeptide ratios can give important information in vector design optimization leading to CHO cell lines with optimized antibody assembly and preferred product quality.