Possible misinterpretation of the mode of action of therapeutic antibodies in vitro: Homotypic adhesion and flow cytometry result in artefactual direct cell death

摘要

Two groups have recently proposed that type II anti-CD20 monoclonal antibodies (mAbs) B1 (tositumomab) and GA101, as well as anti-HLA-DR antibody (L243), induce strong homotypic adhesion and direct cell death. They claim, on the basis of annexin V, propidium iodide (PI), and flow cytometric analysis, that up to 80% of cell death occurs after 24 hours of treatment with these mAbs.