Effect of epratuzumab on the surface levels of antigens on NHL cell lines. Daudi (A) or Raji (B) Burkitt lymphoma cells (1 × 105 cells) were treated overnight with 10 µg/mL epratuzumab or an isotype control mAb (labetuzumab) in the presence, or absence, of PBMCs (1 × 106) or goat-anti-human IgG (20 µg/mL) as a cross-linking second antibody. Repeat experiments gave reproducible results. Each plot is shown as the % MFI of the isotype control treatment. Each sample was evaluated in triplicate. Error bars represent SD. Significantly less than control treatment: ***P < .0001; **P < .001; *P < .05.