Peak antibody production is associated with increased oxidative metabolism in an industrially relevant fed‐batch CHO cell culture

Abstract

Cell metabolism can vary considerably over the course of a typical fed-batch antibody production process. However, the intracellular pathway alterations associated with various phases of growth and antibody production have yet to be fully elucidated using industrially relevant production hosts. Therefore, we performed (13)C labeling experiments and metabolic flux analysis (MFA) to characterize CHO cell metabolism during four separate phases of a fed-batch culture designed to closely represent industrial process conditions. First, we found that peak specific growth rate was associated with high lactate production and minimal TCA cycling. Conversely, we found that lactate metabolism switched from net production to net consumption as the culture transitioned from peak growth to peak antibody production. During the peak antibody production phase, energy was primarily generated through oxidative phosphorylation, which was also associated with elevated oxidative pentose phosphate pathway (oxPPP) activity. Interestingly, as TCA cycling and antibody production reached their peaks, specific growth rate continued to diminish as the culture entered stationary phase. However, TCA cycling and oxPPP activity remained high even as viable cell density began to decline. Overall, we found that a highly oxidative state of metabolism corresponded with peak antibody production, whereas peak cell growth was characterized by a highly glycolytic metabolic state.

A Cyclin Distributed Cell Cycle Model in GS-NS0

“…In addition, lactate is also consumed (Q Lac ) [14,55], which in this case was modelled and triggered by the depletion of glutamate. Antibody production (q i , Equation 17) is specific for each cell cycle phase.…”

“…Recently, metabolic flux analysis (MFA) has become a key tool for the study of mammalian cell cultures aiming at improving productivity and product quality. These studies [11][12][13][14] provide valuable insight on cell behaviour and assist in understanding cell metabolism. However, they neglect the intrinsic heterogeneity (e.g.…”

Proteomic Analysis of Bioreactor Cultures of an Antibody Expressing CHOGS Cell Line that Promotes High Productivity

“…To meet this demand, a variety of strategies have been employed to develop efficient biopharmaceutical manufacturing processes. These strategies include: 1) maximizing the productivity of the manufacturing cell line by the judicious use of expression systems for optimal transcription and translation of the therapeutic protein [2]; 2) engineering the transfection host cell line for efficient post-translational modification and secretion [3]; and 3) improving the cell culture process including media optimization [4][5][6][7][8], developing advanced feeding strategies [9,10] which in turn increases the culture density. Additionally, robust and highly productive host cell lines can be deployed by increasing the efficiency of gene expression that regulates proliferation [11] survival and longevity [12][13][14].…”

Scale-down of CHO cell fed-batch cultures

“…Martínez et al 61 showed that a CHO cell line grown in a batch culture had a six times higher energy efficiency when consuming lactate as compared to the situation where lactate was produced. Using isotopic labeling in combination with metabolic flux analysis, Sengupta et al 72 and Templeton et al 73 both reported higher metabolic fluxes through the pentose phosphate pathway (PPP) and TCA cycle during the stationary phase as compared to the growth phase of CHO cell cultures. Furthermore, Templeton et al 73 showed that the high PPP and TCA activities are associated with peak mAb production.…”

“…Using isotopic labeling in combination with metabolic flux analysis, Sengupta et al 72 and Templeton et al 73 both reported higher metabolic fluxes through the pentose phosphate pathway (PPP) and TCA cycle during the stationary phase as compared to the growth phase of CHO cell cultures. Furthermore, Templeton et al 73 showed that the high PPP and TCA activities are associated with peak mAb production. Results from Wahrheit et al 74 suggested that the metabolic shift in different culture phases of CHO cells is controlled by glycolytic regulation which affects the intracellular pyruvate availability.…”