SDF-1 stimulation induces migration and Ral activation in B cells. (A) DT40, Ramos, and Namalwa B-cell lines, and human tonsillar B cells, were allowed to migrate for 4 hours in the absence (c) or presence of 100 ng/mL SDF-1 (SDF-1) in Transwells (shown as the mean ± SD of triplicates). (B) DT40 cells were allowed to migrate for 4 hours in the absence (−) or presence (+) of 100 ng/mL SDF-1 in the upper or lower compartment of Transwells, as indicated (shown as the mean ± SD of triplicates). (C) DT40, Ramos, and Namalwa B-cell lines, and human tonsillar B cells, were stimulated for the indicated periods of time with 100 ng/mL SDF-1 and lysed, and the amount of Ral-GTP in the lysates was determined by pull-down assay (PD) using GST-RalBP-RBD fusion protein. As a control, total lysates (TLs) were immunoblotted and probed using anti-Ral antibodies. (A,B) All relevant comparisons (eg, migration in absence versus migration in presence of SDF-1) were significantly different (P < .05). (A-C) The results are representative of at least 2 independent experiments.