Prolonged autophagy induction correlates with host cell protein reduction in CHO cell culture

Autophagy, a cellular recycling process regulated by the CLEAR signaling pathway, plays a pivotal role in maintaining cellular homeostasis. We hypothesize that this process may regulate and reduce high‐risk host cell proteins (HCPs) levels by targeting intracellular proteins and organelles for degradation. This study investigates the relationship between autophagy induction and the reduction of HCPs, including polysorbate‐degrading enzymes (PSDEs), to enhance the stability of therapeutic biologics such as monoclonal antibodies (mAbs). Using clonal analysis, we identified upregulation of the CLEAR pathway in one clone, correlating with a significant reduction in lipase activity and PSDE abundance. Furthermore, autophagy modulators, such as 3‐methyladenine (3‐MA), selectively decreased PSDE levels in both glucose‐supplemented batch culture and fed‐batch cultures. This resulted in a 62% reduction in lipase activity that corresponded to a 22% improvement in polysorbate‐80 stability. Additionally, 3‐MA treatment increased mAb specific productivity and altered glycosylation profiles, increasing afucosylation and galactosylation levels. These findings highlight autophagy induction as a promising strategy to modulate product quality profiles and reduce high‐risk HCPs in biologics production.