Maximization of a foreign protein production in serum-free suspension culture of recombinant CHO cells

Abstract

To achieve enhanced cell growth and increased product concentration in serum free media, three non-animal derived hydrolysates were used as additive to serum-free basal medium (SF-A, SF-B) previously developed in our laboratory. Following the statistical design, Simplex Lattice, 10 kinds of serum free media supplemented with various proportions of yeastolate, soy hydrolysate, and wheat gluten hydrolysate (total 5g/L) were prepared. Each of the ten media was used in batch cultures of three rCHO cell lines, producing ABC antibody (C11-08), anti-4-1bb antibody (H-1-5), and human TPO (R-2-3-2), respectively. For the C11-08 and H-1-5 cell lines, the maximum viable cell concentration was decreased or increased by about 0.7- 1.6 fold compared to the control medium, which had no supplementation of hydrolysate. The Maximum product concentration was increased by over 2-fold in all media except for the medium supplemented with only wheat gluten. For the R-2-3-2 cells, yeastolate was the most suitable additive unaccompanied by other hydrolysates. The effect of each medium was analyzed by the statistical program, Design-Expert®, to reconstitute the mixture ratios of the three hydrolystes for high growth and high production. The resulting mixture for high growth, gave a maximum viable cell concentration increased by about 1.3 - 1.6 fold compared to the control medium and in the mixture for high production gave a maximum product concentration increased by about 2 - 7 fold. Effects of the hydrolysate mixtures for high growth and high production were maintained during serum free adaptation for 6 passages and remained after serum free adaptation in C11-08 cell lines. To investigate clonal variation of recombinant Chinese hamster ovary (rCHO) clones in response to culture pH and temperature, serum-free suspension cultures of two antibody producing CHO clones (clone A and B), which were isolated from the same parental clone by the limiting dilution method, were performed in a ...