We are having some difficulties with expression of one of our proteins in 293. We are considering trying CHO instead and possibly changing to a CHO platform for consistency with our manufacturing cell line. Is there any reason that you would recommend keeping both 293 and CHO as transient expression systems or would adopting a CHO platform be fine?

Answer

We have seen multiple instances where a protein that does not express in Expi293, or expresses at a very low level, is expressed well in the ExpiCHO system. At this time, there is not a consensus understanding as to which proteins express better in 293 cells vs. CHO cells, however, our experiences and some data shared from independent labs seems to suggest that if you were to run just one system to produce all of your proteins, that ExpiCHO would likely be the system to pick. Additionally, as you mention, the relevance of the protein generated in ExpiCHO to your production cell line is certainly also something that should be considered, as this allows for a more seamless workflow from discovery to clinic. Lastly, whether to keep a 293 system and a CHO system is based on the specific needs of your lab: for instance, if you are making protein reagents where human post-translational modifications are desired, then having a 293 system makes sense. If you are expressing only candidate therapeutics, then ExpiCHO would certainly be your first choice. Many/most labs that have the ability to run both systems are doing so, providing them with two options to best generate their proteins of interest in the most relevant cell line and providing the greatest likelihood that they will get the protein they need from either the Expi293 or the ExpiCHO system.