Optimization of CHO-S and HEK 293 culture media by supplementation with non-animal derived components

Mammalian cells are the most common host for the production of therapeutic proteins, as well as vaccines and viral vectors for gene therapies. CHO and HEK 293 cells are among the most widely used cell lines. The culture medium composition is a critical element in these bioprocesses. In one side, it has to support cell growth and product formation. In the other side, it has to be chemically defined and animal-derived component free, particularly avoiding the use of bovine serum, that represents a safety hazard as well as a source of unwanted contamination.

Several commercial media have been developed to achieve these requirements, and today there are a number of media available for CHO and HEK 293 cells. However, not all the media are equally valid for all cell lines, and an initial screening is therefore necessary. One clear disadvantage of these commercial media is that they are proprietary and their exact composition is not known by the user.

Additionally, commercial media can be supplemented to improve their performance in supporting a given cell line. Non-animal derivative and well known compounds should be always used. The supplements need to be carefully selected and their optimal conditions determined in order to achieve the best results. Design of Experiments methodologies are a very efficient tool in such optimization work. To be also considered that any supplement may be toxic if added in excess, and that different components can have cross effects when used together.

The presentation will show two study cases where such a methodology has been employed successfully in the optimization of commercial media supplementation with compounds such as r-insulin, r-transferrin, selenium and lipids to sustain CHO and HEK 293 bioprocesses. These improvements reflect directly in the obtention of high product titers.