Chinese Hamster Ovary (CHO) cells are a type of mammalian cell line that has become central to the biotechnology industry. These cells are widely used as a “cellular factory” to produce complex biological molecules, particularly therapeutic proteins. Their ability to generate these sophisticated molecules in large quantities makes them indispensable for developing many modern medicines.
Understanding CHO Cells
CHO cells originated from the ovaries of Chinese hamsters in the 1950s. These cells were isolated and expanded, establishing a foundational cell line. Since then, CHO cell variants have been developed and optimized for research and industrial applications.
As a mammalian cell line, CHO cells share similarities with human cells in their cellular machinery. They grow robustly with a rapid doubling time of around 12 hours, facilitating expansion in laboratory and industrial settings. Their ability to be cultured in vitro, meaning outside a living organism, was key to their widespread adoption.
Biological Advantages for Bioproduction
CHO cells offer several biological advantages for bioproduction. They can perform complex post-translational modifications (PTMs) on proteins, such as glycosylation. These modifications add sugar molecules to proteins after synthesis, which is important for their function, stability, and interaction within the human body. Unlike bacterial or yeast systems, CHO cells create human-like glycosylation patterns, reducing adverse immune reactions in patients.
They also adapt well to high-density suspension culture, growing while suspended in liquid rather than requiring a surface. This is ideal for large-scale bioreactors, enabling efficient and cost-effective manufacturing of therapeutic proteins. CHO cells maintain genetic stability over many generations, ensuring consistent product quality and yield during long production runs.
Additionally, CHO cells have a favorable safety profile compared to human-derived cell lines. Being of hamster origin, they pose a low risk of transmitting human pathogens, which is important for pharmaceutical products. This safety, combined with their robust nature and protein modification capabilities, makes them a preferred host cell line.
Primary Applications in Biopharmaceutical Manufacturing
CHO cells are widely used in the biopharmaceutical industry to produce diverse therapeutic proteins. Their primary application is manufacturing monoclonal antibodies (mAbs). These specialized proteins target specific cells or molecules, and approximately 70% of therapeutic mAbs are produced using CHO cells.
Beyond mAbs, CHO cells produce various recombinant proteins, including hormones, enzymes, and growth factors. For example, the thrombolytic medication alteplase, used for treating clot-inducing ailments, was an early commercially available recombinant protein produced from CHO cells, approved by the FDA in 1987. These biopharmaceuticals treat conditions like autoimmune diseases, cancer, and other chronic illnesses.
Some vaccines also use CHO cell technology. Their ability to perform complex post-translational modifications, often necessary for protein functionality and biocompatibility, makes them suitable for these applications. This versatility allows them to generate many protein-based therapeutics that significantly impact human health.
Continuous Innovation in CHO Cell Systems
Research and development efforts continually enhance CHO cell technology, improving protein yield and quality. Genetic engineering techniques optimize CHO cell lines. Scientists introduce specific genes to boost desired protein production or modify existing genes to refine protein characteristics and improve cellular metabolism.
Improvements in cell culture media are also a key innovation. Developing serum-free and chemically defined media reduces contamination risk and simplifies purification, leading to safer, more consistent products. Advances in bioreactor design and process control strategies increase efficiency. These enhancements allow precise monitoring and regulation of environmental conditions like pH, temperature, and dissolved oxygen, ensuring optimal cell growth and protein production. CHO cell systems remain at the forefront of biopharmaceutical manufacturing, evolving to meet the growing demand for therapeutic proteins.