Analysis of Tubespins as a suitable scale‐down model of bioreactors for high cell density CHO cell culture

Abstract

High cell density (HCD) culture increases recombinant protein productivity via higher biomass. Compared to traditional fed-batch cultures, HCD is achieved by increased nutrient availability and removal of undesired metabolic components via regular medium replenishment. HCD process development is usually performed in instrumented lab-scale bioreactors (BR) that require time and labor for setup and operation. To potentially minimize resources and cost during HCD experiments, we evaluated a 2-week 50-mL Tubespin (TS) simulated HCD process where daily medium exchanges mimic the medium replacement rate in BR. To best assess performance differences, we cultured 13 different CHO cell lines in simulated HCD as satellites from simultaneous BR, and compared growth, metabolism, productivity and product quality. Overall, viability, cell-specific productivity and metabolism in TS were comparable to BR, but TS cell growth and final titer were lower by 25 and 15% in average, respectively. Peak viable cell densities were lower in TS than BR as a potential consequence of lower pH, different medium exchange strategy and dissolved oxygen limitations. Product quality attributes highly dependent on intrinsic molecule or cell line characteristics (e.g., galactosylation, afucosylation, aggregation) were comparable in both scales. However, product quality attributes that can change extracellularly as a function of incubation time (e.g., deamidation, C-terminal lysine, fragmentation) were in general lower in TS because of shorter residence time than HCD BR. Our characterization results and two case studies show that TS-simulated HCD cultures can be effectively used as a simple scale-down model for relative comparisons among cell lines for growth or productivity (e.g., clone screening), and for investigating effects on protein galactosylation. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:490-499, 2017.

Process design and development of a mammalian cell perfusion culture in shake‐tube and benchtop bioreactors

“…This procedure was performed on a daily basis over 14 days to evaluate the maximum VCD at a constant perfusion rate of 1 RV/day. Similar procedures were presented before (Gomez et al, ; Sieck et al, ; Villiger‐Oberbek et al, ).…”

“…Shake‐tube (ST) bioreactor systems represent a less expensive small‐scale reactor system (Jordan & Jenkins, ) that have been recently considered as suitable screening device for perfused cell culture systems (Gomez et al, ; Sieck, Schild, & von Hagen, ; Villiger‐Oberbek, Yang, Zhou, & Yang, ). In particular, the possibility of screening cell clones and media formulations in a daily discontinuous batch‐refeed mode has been demonstrated.…”

Development of a shake tube‐based scale‐down model for perfusion cultures

“…As mentioned above, when using STs as scale‐down model for batch and continuous processes (Gomez et al, ; Villiger‐Oberbek et al, ; Xie et al, ; Zhang et al, ), the most critical parameter for operation at high VCDs is sufficient gas liquid mass transfer, both oxygen supply and CO 2 removal. Considering the operation in an orbital shaken incubator the following parameters affect the gas transfer: Shaking diameter, shaking speed, filling volume, and shaking angle.…”

A novel scale‐down mimic of perfusion cell culture using sedimentation in an automated microbioreactor (SAM)

“…It has been shown that cell growth, peak viable cell density as well as titer are lower in this approach than in standard bench‐scale bioreactors. In terms of product quality, glycosylation was comparable but other attributes like deamidation and C‐terminal lysine clipping were found to be lower . Another study using this application of spin‐tubes showed a similar growth profile in spin‐tubes and a steady‐state perfusion bioreactor but higher lactate levels were observed.…”