Using CHO for transient expression has not been giving use the productivity we are looking for. Do you think adding lipids or growth factors like insulin or IGF would be helpful?

Answer

The optimization of single factors in a CHO-based transient expression system provides modest gains, at best. In many instances existing transient CHO systems express at 10-50mg/L titers, such that even a 50% increase in titer is not a significant improvement. The ExpiCHO system has been developed from the ground up by identification of a high expressing CHO clone, ExpiCHO-S cells, a new expression media and feed, as well as a new high-efficiency transfection reagent and expression enhancers, all of which when optimized to work together increased protein titers of a human IgG from 20mg/L in the FreeStyleCHO transient system to 3000mg/L in the ExpiCHO system. It is truly through the synergistic interaction of all of the components of the system where these log-fold improvements in protein titers can be observed.