Jean-François Michiels

Scale-up of hepatic progenitor cells from multitray stack to 2-D bioreactors

Promethera Biosciences (Mont-St-Guibert, BE) is developing cell therapies to treat several liver genetic metabolic diseases, such as the Crigler-Najjar syndrome. Human heterologous adult liver progenitors cells (HHALPCs) were initially cultivated in 2D standard cultivation devices. The present study is investigating the feasibility to cultivate HHALPCs in Xpansion bioreactors, with the following objectives: ➢ The process must be closed ➢ The growth rate and population-doubling level (i.e. the number of times the cells in the population has doubled) must be at least equivalent to the current process in multilayer trays ➢ The process must comply to the cGMP rules ➢ The cells must succeed the quality control (QC) test specifications at the end of cultivation, i.e. cells must remain undifferentiated and show the presence of HHAPLCs markers, while exhibiting the capacity to differentiate toward functional hepatocytes. Integrity® Xpansion™ multiplate bioreactors have been specifically designed to enable an easy transfer from existing multiple-tray-stack processes by offering the same cell growth environment on 2-D hydrophylized Polystyrene (PS) plates in a fully closed system. To make the bioreactors compact, the headspace between each plate has been reduced to a minimum (1.3 mm). Gas transfer is made through a semi-permeable silicone tubing mounted in the central column. Additionally, critical cell culture parameters such as pH and DO are controlled and the cell density is automatically monitored via a specific holographic microscope developed by Ovizio

Effects of soy peptone-supplemented medium on CHO-320 cells

A strong tendency is currently emerging to remove not only serum but also any product of animal origin from animal cell culture media during production of biopharmaceuticals. The cell line CHO-320 producing human γ-interferon was cultivated in a serum- and protein-free medium supplemented with a soy peptone (Hy-Soy®, Kerry). Although the addition of this plant peptone to the culture medium resulted in a decreased cell growth, an increase of recombinant protein production was observed. Experiments were conducted to elucidate how the peptone contributes to an increased protein production. Results related to transcription activation, protein glycosylation, apoptotic cell death and protein stability suggested that none of these mechanisms could explain the peptone effect. That soy peptone increases protein translation or improves protein secretion is suggested.