CXCL12 signaling and functional impact on FL B cells. (A) Primary FL B cells pretreated or not (UNT) with the CXCR4 antagonist AMD3100, the BTK inhibitor ibrutinib, or the PI3Kδ inhibitor idelalisib were subjected to chemotaxis assay in response to CXCL12. Results are presented as the mean ± SD of the migration index (n = 6). (B) Primary FL B cells were labeled with carboxyfluorescein diacetate succinimidyl ester, treated or not with AMD3100, and incubated for 2 hours on either CXCL12-Fc–coated wells (left) or ADSC confluent cell monolayer (right). ADSCs were transduced 48 hours before by CXCL12 targeting small interfering RNA (siRNA) or control (Ctrl) siRNA. Adhesion percentage was calculated by comparing the residual fluorescence after adhesion with the fluorescence of the input. Shown is 1 representative experiment of 2 (left) or mean ± SD from 6 experiments (right). (C) Primary FL-B cells were starved for 4 hours and stimulated with uncoated (Ctrl) or CXCL12-Fc–coated beads for 60 minutes. Western blot revealed pSyk, Syk, pErk, Erk, and β-actin. Results are presented as the mean ± SD from 3 experiments, and 1 representative experiment is shown. (D) Primary FL B cells were starved for 4 hours and pretreated or not by ibrutinib before stimulation with uncoated or CXCL12-Fc–coated beads for 60 minutes and quantification of pErk, Erk, and β-actin by western blot. Results are presented as the mean ± SD from 4 experiments; 1 representative experiment is shown. *P < .05.