Conclusion

Results demonstrated that for the recombinant CHO cell line studied, the addition of chemically defined feed to the basal medium produced approximately a four-fold greater protein yield than any of the four different plant hydrolysates used. Also, culture supplementation with different plant hydrolysates in combination with chemically defined feeds provided no advantage in terms of increased protein production over the addition of a chemically defined feed on its own. Supplementing media with plant hydrolysates may not always be the most efficient choice or may not offer the same increases in productivity available from chemically defined feeds. Therefore, when culturing CHO cells for maximum protein production, it may be worthwhile to compare different feed types. Bioreactor studies of a different CHO cell line also demonstrated that chemically defined feeds in the culture provided slightly higher protein yields than the addition of a soy hydrolysate when the two feeds were added at the same concentration. In addition, using a higher concentration of chemically defined feed A on day 0 followed by feed B on day 6 yielded superior bioproductivity and proved the value of including multiple, and sometimes counter-intuitive, feeding strategies when trying to maximize protein production.

In summary, using chemically defined feeds with CHO cell lines not only eliminates the variability associated with using plant hydrolysates, but could also improve the productivity of biopharmaceutical protein manufacture and help move therapeutic proteins into clinical trials more rapidly.

References

1. Mols J, Peeters-Joris C, Wattiez R, Agathos SN, Schneider YJ. Recombinant interferon-gamma secreted by Chinese hamster ovary-320 cells cultivated in suspension in protein-free media is protected against extracellular proteolysis by the expression of natural protease inhibitors and by the addition of plant protein hydrolysates to the culture medium. In Vitro Cell Dev Biol Anim. 2005. Mar–Apr; 41(3–4):83–91.

2. Burteau CC, Verhoeye FR, Mols JF, Ballez JS, Agathos SN, Schneider YJ. Fortification of a protein-free cell culture medium with plant peptones improves cultivation and productivity of an interferon-gamma-producing CHO cell line. In Vitro Cell Dev Biol Anim. 2003 Jul–Aug;39(7):291–6.

3. Luo Y, Chen G. Combined approach of NMR and chemometrics for screening peptones used in the cell culture medium for the production of a recombinant therapeutic protein. Biotechnol Bioeng. 2007 Aug 15;97(6):1654–9.

4. Stein A. Decreasing variability in your cell culture. Biotechniques. 2007 Aug;43(2):228–9.

5. Chun BH, Kim JH, Lee HJ, Chung N. Usability of size-excluded fractions of soy protein hydrolysates for growth and viability of Chinese hamster ovary cells in protein-free suspension culture. Bioresour Technol. 2007 Mar;98(5):1000–5.