Apoptosis of Ramos cells induced by anti-CD20 MoAbs as shown by flow cytometry with light scatter analysis. 10⁶cells/mL were incubated with 10 μg/mL antibodies for 24 hours in the presence or the absence of GAM cross-linker at 50 μg/mL. Pelleted cells were resuspended in fixative (5% formaldehyde, 1% FBS in pH 7.2 PBS), and analyzed by flow cytometry. Apoptotic cells were identified and quantified by flow cytometry according to their smaller size and higher density. The data are representative of five experiments.