By Tracy Worzella, Promega Corporation and Brad Larson, Applications Department, BioTek Instruments, Inc.
Pharmaceutical companies are increasingly exploring new biologic and biosimilar products, and thus increasing monoclonal antibody (mAb) immunotherapeutic research. In keeping with this trend, the European Medicines Agency (EMA) and U.S. Food and Drug Administration (FDA) have each drafted guidelines1,2 for biosimilars product development. Both recommend extensive structural and functional characterization of the proposed therapy, demonstrated in part through antibody-dependent cell-mediated cytotoxicity (ADCC) assays, complement dependent cytotoxicity (CDC) assays and complement activation to “cover all functional aspects of the mAb.” The body uses these cytotoxicity mechanisms of action (MOA) to destroy cells that could otherwise proliferate and cause disease or other maladies.
Here we discuss the principles of a bioluminescent ADCC bioassay used in mAb immunotherapeutic development, and demonstrate how this automated, non-radioactive, cell-based assay provides simple, safe, and reliable methods and results using bioengineered effector cells. The cells are engineered to express the FcγRIIIa receptor, the main Fc receptor (FcR) indicated in ADCC mechanism of action, thereby providing similar results as primary NK cells, without the increased time and effort associated with primary cell purification steps. Additionally, when the assay is automated using BioTek’s Precision™ Microplate Pipetting System and Synergy™ Multi-Mode Microplate Readers, the process is streamlined with less active labor required, and results are more robust than manual methods.