Mammalian cell perfusion cultures: “Intensification by growth inhibition”
May 6-11, 2018
Mammalian cell perfusion processes have regained the focus of attraction for the production of therapeutic proteins, especially as a part of an end-to-end integrated production facility. Besides reduced equipment size, higher volumetric productivities, and enhanced cost efficiency, continuous processes enable stable and steady state operation giving more homogeneous and even improved product quality. However, the knowledge on time and cost effective development and scale-up procedures to obtain a stable process operation and desired product quality control is still limited. The combination of long process duration and the lack of automated high-throughput systems for perfusion demand for an optimized strategy regarding the development and control of these processes.
In this study, mammalian cell perfusion cultures have been performed targeting high volumetric productivities and enhanced process and product quality control. Shake tube cultures revealed suitable starting conditions (cell specific perfusion rate, media composition, flow rates) for process design and control. Different strategies for minimizing cellular growth were tested: a) minimizing cell specific perfusion rate, b) chemical growth inhibition c) environmental growth inhibition by lowering the culture temperature. Active growth inhibition targeted cell cycle arrest to reduce cellular growth and to trigger higher productivities. The loss of product in the bleed was effectively reduced by all strategies. Especially, lower culture temperatures were an effective tool for process intensification leading to increased cellular productivities and reduced cellular growth, while the use of a chemical inhibitor did not lead to higher protein quantities. Flow cytometry revealed that more cells were arrested in the G1 phase, leading to lower cell proliferation. Resulting product quality patterns remained constant within each operation set point and indicated the possibility of enhanced product quality during perfusion cell cultures.
A variety of tools can be used to intensify continuous cultures. A temperature down-shift at the start of the production phase represents the most promising tool for process intensification. The different steps present a systematic and efficient procedure for the development of perfusion cell cultures targeting optimal process performance and tunable product quality control.
Moritz Wolf and Massimo Morbidelli, "Mammalian cell perfusion cultures: “Intensification by growth inhibition”" in "Cell Culture Engineering XVI", A. Robinson, PhD, Tulane University R. Venkat, PhD, MedImmune E. Schaefer, ScD, J&J Janssen Eds, ECI Symposium Series, (2018). http://dc.engconfintl.org/ccexvi/80