Co-expression enhances cloning efficiency and protein production in CHO cells

Chinese hamster ovary (CHO) cell lines are widely used in the biopharmaceutical industry, particularly for the production of monoclonal antibodies and recombinant protein drugs. Recombinant cell lines are typically derived from single-cell clones to ensure product consistency and stability. However, the difficult-to-express recombinant proteins may impair single-cell proliferation, thereby significantly reducing cloning efficiency. In this study, co-expression of insulin-like growth factor-1 (IGF-1) was used to improve the single-cell cloning efficiency. Co-expression of IGF-1 significantly improved bulk pool growth and increased cloning efficiency by 53-196 %. Batch cell culture evaluation studies further demonstrated that IGF-1 co-expression enhanced monoclonal cell density by 29-64 % and recombinant protein yield by 47-89 %. Additionally, the growth profile, titer, and critical quality attributes of selected cell clones remained stable over 60 generations. The results of this study demonstrate that IGF-1 co-expression represents an effective single-cell cloning strategy by significantly enhancing cloning efficiency and enabling stable production of difficult-to-express proteins.