SDF-1 induces chemotaxis in CLL B cells. (A) Blood lymphocytes from 16 CLL patients were assayed in the bare filter chemotaxis assay for migration to buffer (control) or different concentrations of SDF-1. Input and transmigrated cells were stained with anti-CD19 and anti-CD3 MoAbs to determine the percentages of the input CLL B cells that migrated into the chambers. The bars represent the mean values (±SD) for the migration of CLL B cells from 16 different patients. (B) For antibody inhibition, CLL PBMC were preincubated with different concentrations of MoAbs against the chemokine receptors CXCR4 (12G5) or a control MoAb directed against the chemokine receptor CCR3 (7B11) before addition to the chemotaxis assay. The controls were preincubated in buffer alone. Results indicate the relative migration compared with control samples migrating to 100 ng/mL SDF-1 (100%) and represent the mean values ± SD of 2 experiments with CLL B cells from 4 different patients. The stars indicate statistically different values, compared with the controls withP values < .05. (C) SDF-1 attracts CLL B cells by a pertussis toxin-sensitive mechanism. The migration of CLL B cells is completely blocked by pretreatment with 200 ng/mL pertussis-toxin (PT, diamonds). Data represent the mean values ± SEM of CLL B from 16 CLL B patients for the chemotaxis assays (boxes) and 4 different CLL samples for pertussis-toxin treatment (diamonds). (D) Migration of B-CLL cells is partially inhibited by Wortmannin, as selective inhibitor of PI-3 kinase. CLL cells were pretreated with 10, 100, 500, and 2,500 nmol/L concentrations of Wortmannin and subject to the chemotaxis assay in the presence of 100 ng/mL SDF-1. The bars represent the mean values (±SD) for migration of Wortmannin-treated B-CLL cells (n = 6), relative to the migration without the inhibitor. The stars indicate statistically different values, compared with the controls with P values < .05.