Expression and activation of Mac-1 during PMN ADCC.
(A) PMNs and DiD-labeled neuroblastoma cells were incubated alone (control), with hu14.18, or with hu14.18/GM-CSF, and flow cytometry analyses were performed at 30, 60, and 120 minutes. In the example shown, expression of CD11b and the β2-integrin activation epitope were analyzed 60 minutes after the initiation of ADCC with FITC–anti-CD11b (the nonblocking Bear-1 mAb) and mAb24 (+ PE–antimouse IgG), respectively. (B) The percentage of mAb24-positive cells in PMN subpopulations expressing high or low levels of CD11b after 60 minutes of ADCC was determined by gating on these distinct subsets. Binding index (% positive cells × mean fluorescence channel/100) for (C) CD11b and (D) mAb24 was calculated at indicated times. Significant differences compared to controls are indicated by ** for P < .01 and *** for P < .001 (ANOVA). Data are from 1 of 3 experiments that provided similar results.
