Adaptation to serum-free

Andersen et al. (1996) and Andersen (1995) have studied the effect of temperature on the recombinant protein production using a baulovinis/insect cell expression system. In Tables 17.15, 17.16, 17.17, 17.18 and 17.19 we reproduce the growth data obtained in spinner flasks (batch cultures) using Bombyx mori (Bm5) cells adapted to serum-free media (Ex-Cell 400). The working volume was 125 ml and samples were taken twice daily. The cultures were carried out at six different incubation temperatures (22, 26,28, 30 and 32 TT). 

Belloncik S, Akoury WE, Cheroutre M (1997), Importance of cholesterol for nuclear polyhedrosis virus (NPV) replication in cell cultures adapted to serum-free medium, In Maramorosh K, Mitsubashi J (Eds), Invertebrate Cell Culture Novel Directions and Biotechnology Applications, Science Publishers, Enfield, NH, pp. 141-147. 

Serum is classically added to cell cultures to provide hormones, growth factors, binding and transport proteins and other supplemental nutrients. Not all lots of serum have the same potential to support cell growth because they may have lower amounts of these components. Conversely, some lots may be toxic or inhibitory due to adulteration or contamination with microbes or viruses. Such sera may inhibit or kill cells at low serum concentrations due to high endotoxin levels or other inhibitory factors. This effect has nothing to do with the ability of the cells to adapt to serum-free conditions. The first step in serum-free adaptation is, therefore, to select a serum lot that can support growth of the cell line at low serum concentrations. 

Healthy culture of cells to be adapted to serum-free conditions... 

Miyaji H, Harada N, Mizukami T, Sato S, Fujiyoshi N Itoh S (1990) Expression of human lymphotoxin in namalwa KJM-1 cells adapted to serum-free medium. Cytotechnology 4 39-43. 

We have developed human cell lines from several tissues using multiple vectors and approaches new cell lines have been generated by transfection with immortalizing cellular or viral genes followed by continuous passage, subcloning and adaptation to serum-free conditions. These procedures have been carried out in designated laboratories, separated from other cell culture activities. 

Fig. 3.8 Antibody yields from batch cultures for 20 antibody-producing cell lines adapted to serum-free media.

Rodrigues, ME, Costa, AR, Henriques M, Cunnah P, Melton DW, Azeredo J, Oliveira R. (2013) Advances and drawbacks of the adaptation to serum-free culture of CHO-Kl cells for monoclonal antibody production. Appl. Biochem. Biotechnol., 169(4) 1279-1291. 

As different cell fines require different medium compositions, adaptation of a cell fine to grow without serum is quite time consuming, and not all cell fines have been adapted to serum-free or protein-free media. Therefore, for laboratory scale, for example, basic cell culture research or cultivation of primary cells, still mostly complex serum-containing media are common. In industrial production with estabfished, optimized cell fines, serum-free, bovine-free, and chemically defined media are state of the art. 

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