The cultivation process for CHO cells typically involves several steps, including cell line development, seed culture, inoculation, cell expansion, and protein production. Here’s a general overview of the CHO cultivation process:
- Cell line development: CHO cells are genetically manipulated to express the desired recombinant protein. This involves transfecting the CHO cells with a plasmid containing the gene of interest, followed by selection and cloning of stable cell lines that express high levels of the protein.
- Seed culture: The selected CHO cell line is first grown in a small-scale culture vessel, such as a shake flask or a small bioreactor, to generate a seed culture.
- Inoculation: The seed culture is then transferred to a larger bioreactor vessel, where it is inoculated into a nutrient-rich growth medium containing sugars, amino acids, vitamins, and minerals.
- Cell expansion: The CHO cells in the bioreactor vessel are allowed to grow and divide, leading to an increase in cell density and volume. During this stage, the culture conditions, such as pH, dissolved oxygen, temperature, and agitation rate, are carefully controlled to optimize cell growth and protein production.
- Protein production: Once the cell density reaches a certain threshold, protein production is induced by adding a specific inducer or by reducing nutrient levels in the growth medium. The protein of interest is then secreted into the culture medium and can be harvested and purified using various downstream processing methods.
- Harvesting and purification: After the desired protein is produced, the culture is harvested, and the protein is purified to remove impurities, such as host cell proteins, DNA, and other contaminants. The purified protein is then formulated and packaged for use as a therapeutic drug.
Overall, the CHO cultivation process requires careful optimization of culture conditions and monitoring of cell growth and protein production to ensure high yields of pure, functional recombinant proteins.