Introduction
Chinese hamster ovary (CHO) cells are widely employed as a host system for the production of therapeutic antibodies and other biopharmaceuticals. These mammalian cells are favored due to their ability to perform complex post-translational modifications, particularly glycosylation, which is critical for the bioactivity, stability, and immunogenicity of therapeutic antibodies. The adaptability of CHO cells to suspension culture and their capacity for high-yield production make them a dominant platform in the pharmaceutical industry.

Mechanisms of CHO Antibody Production
1. Cell Line Development
The first step in CHO antibody production is the development of a stable cell line capable of efficiently expressing the target antibody.
• Transfection: Recombinant DNA encoding the heavy chain and light chain of the antibody is introduced into CHO cells via electroporation or lipid-mediated transfection.
• Selection and Amplification: Selection markers such as dihydrofolate reductase (DHFR) or glutamine synthetase (GS) help isolate high-yielding clones. Multiple rounds of screening are employed to identify stable clones with consistent high expression levels.
• Scale-up: The selected clones are expanded to large-scale cultures, ensuring stable antibody expression throughout production.
2. Glycosylation and Post-Translational Modifications
CHO cells perform mammalian-specific glycosylation, essential for functions like antibody-dependent cellular cytotoxicity (ADCC).
• Glycan Structure Control: Unlike bacterial or yeast systems, CHO cells generate glycosylation patterns similar to those in human antibodies. However, glycosylation can be influenced by environmental factors such as medium composition, pH, and oxygen levels, requiring precise control to maintain consistency and efficacy.
• N-Glycosylation and O-Glycosylation: The glycosylation of the Fc region of antibodies regulates interactions with Fc gamma receptors (FcγRs), impacting immune functions such as ADCC and complement-dependent cytotoxicity (CDC).
3. Culture Systems and Production Strategies
Two primary strategies are commonly employed in CHO cell culture for antibody production:
• Fed-Batch Culture: In this approach, nutrients are periodically added to a fixed-volume system to extend the production phase. Fed-batch cultures are widely used due to their simplicity and ability to achieve high yields.
• Perfusion Culture: In perfusion systems, the culture medium is continuously replaced, and waste products are removed, supporting prolonged cell viability and higher productivity. Although this method is effective for long-term production, it involves more complex operations and higher costs.
Key culture parameters—such as dissolved oxygen, pH, glucose levels, and ammonia accumulation—must be closely monitored and optimized to maintain cell health and maximize antibody expression.
4. Protein Folding and Aggregation Management
The complex structure of antibodies requires correct disulfide bond formation and folding to ensure functionality. Misfolding or aggregation can reduce stability and bioactivity.
• Molecular chaperones and foldases assist with proper folding inside cells and prevent misfolding or aggregation.
• Lowering culture temperatures or using specific additives can also minimize aggregation, enhancing the quality and yield of antibody production.


Applications of CHO-Derived Antibodies
1. Oncology
CHO-produced monoclonal antibodies (mAbs) play an essential role in cancer therapies. Antibodies such as trastuzumab (Herceptin) and rituximab (Rituxan) target specific antigens on tumor cells, mediating immune responses like antibody-dependent cellular cytotoxicity (ADCC) and complement activation.
2. Autoimmune Diseases
CHO-derived antibodies, such as adalimumab (Humira) and infliximab (Remicade), are widely used to treat autoimmune diseases. These biologics block key pro-inflammatory molecules, such as TNF-α, thereby reducing disease activity in conditions like rheumatoid arthritis and Crohn's disease.
3. Infectious Diseases
Monoclonal antibodies developed in CHO cells are also being investigated for treating infectious diseases. Antibodies targeting viral proteins, such as those developed for COVID-19, can neutralize pathogens and reduce disease severity.
4. Biosimilars Development
CHO cell systems enable the production of biosimilars—replicas of original biologic drugs. Biosimilars offer more affordable alternatives to existing antibody therapeutics, expanding patient access to life-saving treatments.
5. Diagnostics
In addition to therapeutic applications, CHO-derived antibodies are critical components in diagnostic assays, such as ELISA and immunohistochemistry (IHC), facilitating the detection of biomarkers in research and clinical settings.

GenScript Solutions in CHO Antibody Production
GenScript offers a variety of services and products to streamline CHO-based antibody production:
• CHO Stable Cell Line Development Services: Accelerate the creation of high-yield cell lines with optimized antibody expression.
• TurboCHO™ Platform: Offers high-throughput production of purified antibodies in just 5 business days from gene to antibody.
• TurboCHO™ High Throughput Platform: Offers the most cost-effective option for small-scale recombinant antibodies.

Conclusion
CHO cells have become a cornerstone of antibody production due to their ability to synthesize complex therapeutic proteins with appropriate glycosylation patterns. Optimizing cell culture conditions, media, and downstream processing ensures the consistency, efficacy, and safety of CHO-derived antibodies. As the demand for biologics continues to grow, innovations in CHO-based production systems, such as cell line engineering and media optimization, will further enhance therapeutic outcomes and streamline the manufacturing process.