Extracellular insulin degrading activity creates instability in a CHO-based batch-refeed continuous process

Area of Science:

• Biotechnology
• Cell Culture Technology
• Bioprocess Engineering

Background:

• Recombinant Chinese hamster ovary (CHO) cell lines are crucial for biopharmaceutical production.
• Batch-refeed continuous processes are widely used for large-scale cell culture.
• Intermittent process upsets can negatively impact productivity and product quality.

Purpose of the Study:

• To investigate the cause of occasional process upsets in a batch-refeed continuous culture of CHO cells.
• To identify the factors contributing to halted cell growth and reduced viability.
• To understand the role of insulin in the observed cell culture instability.

Main Methods:

• Monitoring cell growth, viability, and key media components during batch-refeed continuous culture.
• Analyzing insulin levels and identifying potential degradation factors in spent medium.
• Correlating process upsets with specific events or conditions in preceding culture passages.

Main Results:

• Process upsets were consistently associated with early depletion of insulin during a passage.
• Insulin depletion was primarily caused by an insulin-degrading activity released by CHO cells.
• This degrading activity was found to be present in the medium from the preceding cell culture passage.

Conclusions:

• Cellular release of insulin-degrading activity is a key factor causing instability in CHO cell batch-refeed continuous processes.
• Proactive management of insulin levels and mitigation of cellular degradation activity are essential for robust bioprocesses.
• Understanding and controlling intracellular and extracellular factors affecting nutrient stability is critical for optimizing recombinant protein production.