Advances of Serum-Free Medium for CHO Cells for the Production of Recombinant Protein

Mammalian expression system has become the main expression system for the production of recombinant protein, due to its similarity of the post-translational modification to the human cells. CHO (Chinese hamster ovary) cells are ideal mammalian expression hosts for recombinant protein production. The medium used for routine cell culture requires supplemental serum for normal growth. However, due to the disadvantages of serum, such as different sources and batches, difficulty in downstream separation and purification, and potential risk of mycoplasma contamination. Therefore, serum-free culture medium is required for CHO cells to produce recombinant protein drugs to avoid the above problems. In recent years, a lot of researches have been performed on serum-free medium, and remarkable progress has been made. In this review, the characteristics of CHO cells, the basic components and functions of serum-free medium, and the functions of some special additives are reviewed.