Mediation of ADCC by HCD122 and rituximab in patient B-CLL cells. Freshly isolated human NK cells were used as the effector (E) cells in the ADCC assay. Calcein-labeled patient CLL target (T) cells were mixed with the NK cells at an E/T ratio of 10 to 1. Percentage specific lysis was calculated as described in “Statistical analysis.” Graph represents data from one representative CLL patient (patient C4 in Table 2). Values are mean (± SD) of triplicate measurements.