In another study, antibodies produced via MaxCyte transient transfection were characterized and compared to those produced by a stably transfected cell line (Figure 2). CHO cells were transiently transfected with an antibody expression plasmid, and secreted antibody samples were collected for analysis via electrophoresis.
The same antibody produced via a stable CHO cell line was used as a reference during analysis. Similar to previous reports, no differences between transiently and stably produced antibodies from CHO cells are observed when examined via reducing and nonreducing SDS-PAGE and isoelectric focusing.
Significant efforts have been made to increase CHO cell antibody productivity from both transient and stable expression systems. A range of factors have been identified that affect productivity including the use of specific CHO cell lines and various cell culture parameters such as cell density, feeding conditions, media additives, and culture temperature.
A variety of post-transfection parameters were examined, and the combination of a hypothermic temperature shift, the addition of sodium butyrate, and nutrient feed was found to significantly improve antibody titers achieving levels greater than 1.2 g/L (Figure 3).