High throughput screening for antibody induced complement-dependent cytotoxicity in early antibody discovery using homogeneous macroconfocal fluorescence imaging.

Complement-dependent cytotoxicity (CDC) represents an important Fc-mediated effector function of antibodies and is a quality often sought in candidates for therapeutic antibody development in cancer. Antibodies inducing potent CDC are relatively rare as the ability to induce CDC is strongly dependent on the antigen and epitope recognized as well as antibody isotype. To allow the identification of antibodies with optimal CDC characteristics in early stages of antibody discovery, we developed a homogeneous high throughput CDC assay, compatible with 384 and 1536 well formats and which therefore allows direct functional screening of very large panels of antibodies. Results obtained with our newly developed CDC method are consistent with those obtained with conventional assays. The assay proved to be robust, reliable over a wide reading window, easy to perform with low hands-on, high throughput, cost effective and applicable to crude hybridoma samples as typically available in early hybridoma discovery. In conclusion, we developed a novel high throughput assay for the identification of therapeutic antibody lead candidates with optimal CDC characteristics from large antibody libraries.