Antibodies mark invader cells for destruction in the pathway termed Antibody Dependent Cellular Cytotoxicity (ADCC), which comprises part of the adaptive immune response. After an antibody coats the target cell surface effector cells, such as natural killer (NK) cells, bind the Fc portion of the antibody, causing the Fc receptors to be cross-linked and activating the effector cell.
In vitro ADCC assays are the first step in evaluating the therapeutic potential of an antibody. SBH Sciences now offers ADCC assay services, based upon the Promega ADCC Reporter Bioassay™ technology.
Traditional ADCC assays require donor peripheral blood mononuclear cells (PBMCs) as effector cells and typically monitor apoptosis by measuring the release of a radioactive marker. PBMC variability can lead to inconsistent results, and the use of radioactive markers complicates safety.
The Promega ADCC Reporter Bioassay™ uses engineered effector cell that stably express the FcγRIIIa receptor, coupled to luciferase expression. Activated effector cells emit luminescence in the presence of Bio-Glo™ substrate. No donor cells or radioactive markers are needed.
Effector cells and target cells were mixed at a ratio of 6:1 (75,000 effector cells/well) and incubated for 6 hours at 370C. Bio-Glo™ reagent was added, and luminescence was measured using a Promega GloMax Multi Detection System™. A 70 fold induction of ADCC activity was detected at 1ug/ml α-CD20.
Effector cells and target cells were mixed at a ratio of 12.8:1 (64,000 effector cells/well) and incubated for 6 hours at 370C. Bio-Glo™ reagent was added, and luminescence was recorded using a CLARIOstar BMG Labtech 96-well plate reader. Herceptin-treated cells showed a 57-fold increase in luminescent signal versus control wells at 0.5 ug/ml.
