Identification and classification of host cell proteins during biopharmaceutical process development

Area of Science:

• Biopharmaceutical Manufacturing
• Process Development
• Analytical Chemistry

Background:

• Advances in upstream processing have increased antibody titers, complicating downstream purification.
• Current bioprocess development often segregates upstream and downstream stages.
• Optimizing upstream conditions with downstream purification in mind can mitigate purification challenges.

Purpose of the Study:

• To investigate the impact of extended cell culture duration on critical quality attributes of CHO-expressed IgG1.
• To analyze host cell protein (HCP) carryover during Protein A purification.
• To understand cellular behavior and HCP profiles in relation to product quality.

Main Methods:

• Cultivation of CHO-expressed IgG1 in 2L bioreactors over 17 days.
• Sampling at multiple time points (Days 8, 10, 13, 15, 17).
• Centrifugation, filtration, Protein A chromatography, and mass spectrometry (MS) for HCP identification.

Main Results:

• Antibody titer increased with culture duration, but product quality declined.
• Post-Protein A HCP levels rose significantly (72 to 475 peptides detected by MS).
• Product monomer percentage decreased from 98% to 95.5% by Day 17.
• Increased abundance of stress response and cell age-related HCPs observed in later stages.

Conclusions:

• Integrating upstream and downstream process development is crucial for efficient antibody purification.
• Extended cell culture duration negatively impacts product quality due to increased HCPs.
• MS analysis provides valuable insights into specific HCPs retained during mAb purification, aiding process optimization.