Cxcr4 desensitization limits the entry of B cells into cycle. (A) Representative fields from time-lapse imaging of splenic B cells from WT X Blimp1-GFP and Cxcr4^+/1013 X Blimp1-GFP mice cultured in the presence of LPS. Images were taken using the Biostation at 46 and 67 hours after stimulation. Scale bar: 20 µm. (B) Quantification of GFP⁺ cells/ imaged fields during LPS stimulation of splenic B cells. GFP fluorescence detection was measured up to 90 hours after stimulation using the Incucyte technology. (C-F) Splenocytes from WT and Cxcr4^+/1013 mice were loaded with CTV and cultured in presence of LPS for 3 days. (C) Representative histograms for CTV dilution in LPS stimulated B cells at day 2. (D) Frequency of B cells present in each CTV dilution generation at days 2 and 3. (E) Representative dot plots for CTV dilution during PB (CD138⁺) differentiation at day 2 after LPS stimulation. (F) Frequency of PBs present in each CTV dilution generation at days 2 and 3. (G) Representative plots showing the different phases of the cell cycle (G0, G1, S, G2-M) for splenic B cells at day 2 after LPS stimulation stained with DAPI and for Ki-67. (H-I) Frequency of splenic B cells and PBs in each cell cycle phase at day 2 after LPS stimulation. Results are from 2 independent experiments (C-I) or 1 representative experiment of 2 (A-B) (mean ± SEM, n = 2-7 for C-H; n = 2 for A-B). Mann-Whitney U test was used to assess statistical significance (*P < .05, **P < .01, ***P < .001).