Our group has been tasked with producing a fairly high amount of protein for pre-clinical study. We’d rather not take the time and just use transient expression instead. What is the upper limit in terms of production? Range of expected titer?

Answer

For a high-expressing human IgG, pre-purification titers of up to 3g/L have been obtained in the ExpiCHO expression system, titers previously only attained in stable cell lines. For many other antibodies, ranges from 100’s mg/L to multiple grams/L have been generated in external laboratories. Similarly, the ExpiCHO system does an excellent job expressing antibody-like (ie bispecifics) and non-antibody proteins as well. One of the goals of the ExpiCHO system development was to allow for this seamless transition from discovery to pre-clinical studies using CHO-derived protein. Assuming that your protein expresses at reasonable titers, there should be no reason why this would not be possible. In many instances we have seen that proteins that express well in transient 293 express even better in ExpiCHO, with one study showing a nearly 3-fold improvement in titers across a panel of 20 mAbs, with every one of the mAbs expressing higher in ExpiCHO than in the Gold Standard Expi293 system. We have also seen numerous instances where a protein that does not express, or expresses very poorly, in 293 or other CHO systems, expresses well in the ExpiCHO system.