Chinese Hamster Ovary (CHO) cells are a cell line derived from the Chinese hamster. Established in the 1950s, these cells are now widely used in biotechnology and medicine. Their widespread adoption is due to their ability to produce complex biological molecules highly compatible with human systems, playing an important role in developing many life-saving treatments.
Unique Characteristics for Biopharmaceutical Production
CHO cells possess several attributes that make them highly suitable for producing biopharmaceutical drugs. They are known for their high protein expression capabilities, meaning they can produce large quantities of target proteins. In fed-batch cultures, CHO cells can achieve protein yields ranging from 1 to 10 grams per liter of cell culture, making them highly efficient for industrial-scale production.
CHO cells perform proper protein folding and post-translational modifications, like glycosylation. These modifications are crucial for the biological activity, stability, and therapeutic effectiveness of proteins intended for human use. Unlike microbial or plant-based systems, CHO cells add human-like sugar structures, minimizing immune responses in patients.
The adaptability and robustness of CHO cells contribute to their suitability for large-scale manufacturing. They grow efficiently in suspension cultures, allowing cultivation in large bioreactors without solid surfaces. These cells also thrive in chemically defined, serum-free media, reducing contamination risks and simplifying purification. Their tolerance to variations in pH, temperature, and oxygen levels suits them for industrial production.
CHO cells have an established safety record and widespread regulatory acceptance. The first recombinant protein therapeutic produced in CHO cells, tissue plasminogen activator, was approved in 1987. This history builds confidence in them as a reliable platform. Their lower susceptibility to human pathogenic viruses compared to some other mammalian cell lines also contributes to their favorable safety profile.
Manufacturing Therapeutic Proteins and Antibodies
The primary application of CHO cells is the large-scale manufacturing of therapeutic proteins and antibodies, which have significantly impacted the treatment of numerous diseases. Approximately 70% of all approved recombinant protein biopharmaceuticals, including many top-selling drugs, are produced using CHO cells.
Monoclonal antibodies (mAbs) represent a significant class of biopharmaceuticals produced in CHO cells. These antibodies treat conditions including cancers, autoimmune diseases like rheumatoid arthritis and multiple sclerosis, and viral infections. CHO cell production ensures these antibodies have the correct structure for effective function.
Beyond antibodies, CHO cells produce recombinant protein hormones, such as erythropoietin (which stimulates red blood cell production) and certain types of insulin. They also manufacture clotting factors, like Factor IX and Factor VIII, vital for individuals with bleeding disorders such as hemophilia.
Another category includes enzyme replacement therapies (ERTs) for genetic disorders that use CHO cells. For instance, enzymes treating Pompe disease and other lysosomal storage disorders are produced this way. These therapies provide patients with functional enzymes their bodies lack, managing symptoms and improving quality of life.
Broader Applications in Research and Development
While large-scale drug manufacturing is their most prominent use, CHO cells also serve other functions in research and development. They are valuable tools in drug discovery and screening. Researchers use CHO cells as models to test new drug candidates, identifying promising compounds early in development.
CHO cells are also employed in toxicity testing, assessing the safety of new chemical compounds and therapeutic agents. This allows scientists to evaluate cellular responses to various substances, providing important data on potential adverse effects.
In basic biological research, CHO cells contribute to studies on cellular processes, gene function, and protein interactions. Their well-characterized genome and ease of genetic manipulation make them a convenient system for investigating fundamental biological questions. This research can lead to a deeper understanding of human health and disease.
CHO cells are increasingly utilized in vaccine production, particularly for recombinant subunit vaccines. These vaccines incorporate specific viral protein elements produced in CHO cells, which stimulate an immune response. Examples include approved subunit vaccines against respiratory syncytial virus (RSV) and varicella-zoster virus (VZV), as well as some hepatitis B virus (HBV) vaccines.