Process Biochemistry 46 (2011) 1759–1766 Contents lists available at ScienceDirect Process Biochemistry journal homepage: www.elsevier.com/locate/procbio Effects of a soy peptone on -IFN production steps in CHO-320 cells J.-F. Michiels a,∗ , S. Sart a , Y.-J. Schneider a , S.N. Agathos a,b a Institut des Sciences de la Vie, UCLouvain, Croix du Sud, 1348 Louvain-la-Neuve, Belgium b Earth and Life Institute (ELI), UCLouvain, Croix du Sud, 1348 Louvain-la-Neuve, Belgium article info Article history: Received 4 January 2011 Received in revised form 12 May 2011 Accepted 30 May 2011 Keywords: CHO cells Soy peptone Cellular effects Molecular effects Protein translation Protein secretion abstract High quality (glyco)proteins are needed for biopharmaceutical applications. They are generally expressed as recombinant proteins in bacteria, yeast, plant and/or animal cells in culture. Growth media are increas- ingly supplemented with peptones to improve either the cell growth or protein expression or both. To further enhance protein production, it is important to understand the effects of peptones at the cellular and molecular levels. Upon addition of a soy peptone to a cultivation medium of CHO cells, an increased specific productivity was observed. This work aimed at elucidating which main cellular functions are affected by the presence of the peptone. Therefore, hypotheses about putative effects on recombinant protein production steps have been postulated and tested. Although the effects emerge to be multiple, it was found that the peptone increased overall protein translation and recombinant protein secretion. Nonetheless, when other cellular functions (e.g. transcription, glycosylation, proteolytic degra- dation) were examined, no specific effects were observed. Further experiments are needed to probe the mechanisms related to the influence of the soy peptone on these cellular functions. © 2011 Elsevier Ltd. All rights reserved. 1. Introduction Biotechnological and clinical applications of biopharmaceuti- cals require large quantities of high quality (glyco)proteins. Many proteins harbour complex structures and post-translational modi- fications that are necessary for their optimal activity. Such proteins need therefore to be expressed in mammalian or insect cell lines, among which Chinese Hamster Ovary (CHO) cells are the most commonly employed. Furthermore, these cells can be adapted for growth in suspension, which facilitates their large-scale cultivation in stirred tank bioreactors. Animal cells are commonly cultivated in serum-containing media for some applications, like tissue culture engineering. Actually, animal serum contains several essential compounds for cell growth and maintenance such as growth factors, trace elements, vitamins, and hormones [1]. However, serum poten- tially also contains undesirable components, like prions, viruses, and mycoplasma that may contaminate the final product [2–4]. Although serum is still added to the cultivation media of primary cells, biopharmaceutical applications tend to avoid serum, and more generally all reagents of animal origin, for the cultivation of production cell lines. The alternatives to serum for the cultivation of primary cells are the addition of purified/recombinant growth ∗ Corresponding author. Tel.: +32 10473469; fax: +32 10474895. E-mail addresses: jean-francois.michiels@uclouvain.be, michielsjef@yahoo.fr (J.-F. Michiels). factors, which increases the production cost, whereas cheaper alternatives for the cultivation of production cell lines exist [1]. For example, insulin that acts as a mitogen has been successfully replaced by zinc for the cultivation of hybridomas, myelomas and CHO cells [5]. A more recent trend consists in the addition of peptones to serum-free medium to promote cell growth and/or to enhance recombinant protein production [6]. Proteins from meat, yeast or plant have been hydrolysed to manufacture peptones [7]. Prima- tone, a meat hydrolysate, was found to prolong the stationary phase of insect cell culture [8]. Yeast hydrolysate has been shown to improve the cell growth and recombinant protein production of a CHO cell line [9]. The main advantage of plant peptones over meat and yeast peptones is the vanishingly low likelihood of animal- derived contamination. Soy peptone was found to improve both cell growth and protein production of two different CHO cell lines [9,10], whereas rapeseed protein hydrolysate increased the max- imal cell density of the insect cell line Sf-9 [11]. Among peptones tested by Burteau et al. [12], various effects have been observed on both maximal cell density and -IFN production in CHO-320 cells. As shown by the above examples, peptones of different origins have been used successfully as media supplements for several cell lines. Furthermore, the manufacturing process of the peptone affects its performance [7]. For instance, the effects of several soy peptones on CHO cell growth differed according to the peptone manufacturer [13]. The main bottleneck during recombinant protein synthesis in animal cells is considered to occur at the co- and post-translational 1359-5113/$ – see front matter © 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.procbio.2011.05.025