Does the quality of the expressed protein decrease if you push transient expression to gram/L titers?

Answer

The quality of expressed proteins is not necessarily related to high titer. Many factors contribute to protein quality including the molecule itself, transfection conditions, production conditions, and the host cell line. Recently, we observed issues specifically with protein degradation when using the ExpiCHO cell line for several proteins even when using MaxCyte flow electroporation. Interestingly, this issue was not observed for the same protein when using the same transfection method and production process but a different CHO cell line. Thus the selection of a host cell line should not be overlooked as an important factor for minimizing risk for your biotherapeutic candidates.