Figure 3

Biorecognition of PL-RB on surface CD20 of Raji cells. (a),(b) Binding avidity of PL-RB and parental mAbs to surface CD20 of Raji cells. (a) Raji cells were incubated with 10 μg/ml Rituximab, 11B8 and PL-RB and labeled with GAH-488. The cell-bound avidity was evaluated by the MFI of FL-1 and detected by FCM. Black histogram: PBS; Red histogram: Rituximab; Green histogram: 11B8; blue histogram: PL-RB. (b) Raji cells were incubated with 10 μg/ml Alexa Fluor 488/647 labeled Rituximab/11B8 and PL-RB on ice for 1 hour and then assessed by confocal microscope. (c) Dissociation of PL-RB and parental mAbs from Raji cells. Cells were incubated with 10 μg/ml Rituximab, 11B8 and PL-RB, washed and resuspended in culture medium. Samples were taken at 0, 1, 2, 4, 8, 18 and 24 hours, washed, labeled with GAH-488 and analyzed by FCM. Left panel: Numerical data representing the remaining percent of initial binding mAbs or PL-RBs after different time intervals. Data are mean ± SD of at least 3 experiments. Right panel: The histogram represents the fluorescence intensity distribution of Raji cells. Black histogram shows PBS treated cells. (d) Red and blue histograms show the fluorescence intensity distribution after 0 and 24 hours, respectively.