Statistical optimization of culture conditions for expression of recombinant humanized anti-EpCAM single-chain antibody using response surface methodology

The epithelial cell adhesion molecule (EpCAM), is one of the first cancer-associated markers discovered. Its overexpression in cancer stem cells, epithelial tumors, and circulating tumor cells makes this molecule interesting for targeted cancer therapy. So, in recent years scFv fragments have been developed for EpCAM targeting.

Experimental approach:

In this study, an scFv against EpCAM extracellular domain (EpEX) derived from 4D5MOC-B humanized mAb was expressed in Escherichia coli</em> k12 strain, and in order to obtain the optimum culture conditions in chemically defined minimal medium, response surface methodology (RSM) was employed. According to the RSM-CCD method, a total of 30 experiments were designed to investigate the effects of various parameters including isopropyl-b-D-thiogalactopyranoside (IPTG) concentration, cell density before induction, post-induction time, and post-induction temperature on anti EpEX-scFv expression level.

At the optimum conditions (induction at cell density 0.8 with 0.8 mM IPTG for 24 h  at 37 °C), the recombinant anti EpEX-scFv was produced at a titer of 197.33 μg/mL that was significantly consistent with the prediction of the model.

Conclusion and implication:

 The optimized-culture conditions obtained here for efficient production of anti EpEX-scFv in shake flask cultivation on a chemically defined minimal medium could be applied to large-scale fermentation for the anti EpEX-scFv production.