Why Cell Line Screening Is Crucial For Successful Complement-Dependent Cytotoxicity (CDC) Assay Development

A major advancement in oncologic therapies in recent years has been the development of monoclonal antibodies (mAbs) that specifically target tumor-associated antigens. The therapeutic efficacy of these antibodies is heavily influenced by the functional activity of their Fc (fragment crystallizable) region. While the complementarity-determining regions (CDRs) of the antibody are responsible for recognizing and binding to specific tumor antigens, the Fc region mediates the elimination of target cells through several critical immune mechanisms: complement-dependent cytotoxicity (CDC), antibody-dependent cellular cytotoxicity (ADCC), and antibody-dependent cellular phagocytosis (ADCP).

Given the pivotal role of Fc-mediated effector functions in driving antitumor activity, thorough evaluation of these functions is essential during the development of mAb therapeutics. Cell-based potency assays have become a cornerstone of this assessment, providing critical data for both biological characterization and quality control (QC) batch release. These assays not only ensure that the antibody maintains its intended mechanism of action but also support regulatory compliance and consistent therapeutic performance across production lots.