Role of oxidative stress in modulating CHO cell culture performance: Impact on titer and quality attributes of a monoclonal antibody therapeutic

BACKGROUND The enormous success of antibody therapeutics has resulted in attempts to enhance protein expression which requisites high energy demand which leads to oxidative stress as characterized by significant levels of intracellular reactive oxygen species (ROS), disturbing many cellular functions. This study delineates the mechanistic role of oxidants and ROS scavengers in relation to cell viability, apoptosis and mitochondrial membrane potential (MMP), as well as critical quality attributes such as charge heterogeneity. RESULTS Addition of ROS scavengers such as glutathione, N-acetylcysteine (NAC) and ascorbic acid to culture result in decreased levels of ROS (52%), increased MMP (47%) and viable cell populations (42%), as well as reduced cell apoptosis (69%) and a decrease in lysosome activity (38%). These effects rescue cells from damage caused by oxidative stress and DNA fragmentation during the production phase. Cells use the peroxiredoxin reductive pathway for regulation of ROS levels in response to oxidative stress environments. Enzymes involved in ROS reduction were found to be significantly high in antioxidant-treated cells. Treatment with oxidants resulted in decreased titer (47%) and an increase in acidic species (18%), whereas addition of antioxidants resulted in enhancement of titer (38%) as well as abundance in basic variants (24%) of recombinant IgG(1). CONCLUSION Antioxidants improve cell culture performance by alleviating the viable cell pool through activating the intracellular reductive mechanism for maintaining high increment delta?(m), thus reducing apoptosis and enhancing antibody production. Media supplementation with a combination of antioxidants during the production phase is likely to enhance antibody titer and quality. (c) 2022 Society of Chemical Industry (SCI).