Epratuzumab-induced reduction of CD19 and CD22 with monocytes. (A) Daudi cells (1 × 105) were mixed with effector cells (1 × 106) comprising PBMCs, T-cell–depleted PBMCs, or monocyte-depleted PBMCs, which were each derived from the same donor. (B) Daudi cells (1 × 105) were mixed with PBMCs (1 × 106), monocyte-depleted PBMCs (1 × 106), or purified monocytes (5 × 105), which were each derived from the same donor. The cell mixtures were incubated overnight with 10 µg/mL epratuzumab or an isotype control mAb (labetuzumab). The levels of CD19 and CD22 on the surface of Daudi (A, left; B) and the intrinsic B cells (A, right) were measured by flow cytometry and plotted as the % MFI of the isotype control treatment. Each sample was evaluated in triplicate. Error bars represent SD. Significantly less than treatment without effector cells: ***P < .0001; **P < .001; *P < .05.
