pH Condition in temperature shift cultivation enhances cell longevity and specific hMab productivity in CHO culture

Abstract

Controlling cell proliferation during cell culturing is an effective way to improve the production yield in mammalian cell culture. We examined the effect of temperature shifts (TS) under pH control conditions in Chinese hamster ovary cells. When we shifted the culture temperature from 37°C to 31°C before a stationary phase at pH 6.8 (TS/pH 6.8), cell viability remained high, and the final human monoclonal antibody (hMab) concentration increased to 2.3 times that in the culture remaining at 37°C. However, there were no significant effects on the cell viability or production yield with the same TS at pH 7.0 (TS/pH 7.0). The average specific hMab productivity and mRNA level of TS/pH 7.0 were the same as that of TS/pH 6.8. The control of cell growth by the TS or the addition of rapamycin was effective in the maintenance of cell viability, but there was no significant increase of the average specific hMab productivity in the culture where cell proliferation was controlled with rapamycin. The hMab mRNA concentration decreased to 55%-65% at a 37°C culture with the addition of actinomycin D. In contrast, actinomycin D did not affect the mRNA level in the TS culture. This result suggested that the increase in the mRNA level in the TS condition was caused by an increase in mRNA stability. In this study, we show that TS can produce two unrelated effects: a prolongation of cell longevity and an improvement in mRNA stability.

Culture temperature modulates half antibody and aggregate formation in a Chinese hamster ovary cell line expressing a bispecific antibody

“…Increased mRNA levels in CHO cells with lower temperature has been previously reported (Gomez et al, ; Oguchi et al, ). Additionally, for cell line X, the mRNA ratios were also impacted by DNA copy numbers (previously measured, results not shown): LC1 copy number was ~50% of HC1, whereas LC2 copies were 1.2‐fold higher than HC2 copies.…”

“…We anticipated that some culture conditions could potentially alter impurity formation. In particular, culture temperature affects transcript levels in CHO cells (Bedoya‐Lopez et al, ; Gomez et al, ; Mason, Sweeney, Cain, Stephens, & Sharfstein, ; Oguchi, Saito, Tsukahara, & Tsumura, ; Yoon, Kim, & Lee, ) that could potentially mediate B‐Ab folding or correct chain assembly. We found culture temperature modulated two product‐related impurities in cell line X: half B‐Ab and high‐molecular‐weight (HMW) species.…”

Valeric acid induces cell cycle arrest at G1 phase in CHO cell cultures and improves recombinant antibody productivity

“…Chinese hamster ovary (CHO) cells are widely used for the commercial production of therapeutic proteins including antibodies . For high‐level expression of therapeutic proteins in CHO cell cultures, cell proliferation is often controlled by limiting the progression of the cell cycle by genetic manipulation of cell cycle checkpoints , hypothermic or hyperosmolar culture conditions , or chemical agents , because this growth arrest can significantly increase specific productivity ( q p ) . A chemical approach for the cell cycle arrest is easy to implement in industrial processes due to its simplicity.…”

Technological progresses in monoclonal antibody production systems

“…140 Therefore, the most advantageous temperature strategy may be culturing cells at 37 C until a high cell density is reached and then shifting to lower temperatures to achieve higher product titers. 141,142 pH. Along with temperature, pH is considered to be one of the most critical parameters for mammalian cell culture, because of the severe effects its variation can cause to cells.…”