Figure 7.

Cxcr4 desensitization is essential to limit plasmablast maturation and persistence within the BM. (A) PB (B220^loCD138⁺) and PC (B220⁻CD138⁺) numbers in the BM of both WT or Cxcr4^+/1013 mice after NP-LPS immunization at the indicated time points. (B) Blimp1^GFP/+ PBs were generated in vitro from splenic B cells and labeled with CTV for Cxcr4^+/1013 cells and with CTY for WT cells as previously described in Figure 6D and transferred into WT recipient mice. Representative dot plots of PC (red) and PB (blue) gating and total number of transferred Blimp1^GFP/+ PBs and PCs in the BM of recipient mice at days 1 and 2 after transfer. (C) Representative dot plots and quantification of the frequency of CTV⁺ (Cxcr4^+/1013 × Blimp1-GFP) and CTY⁺ (WT × Blimp1-GFP) cells in both the PC (CD138⁺B220⁻) and PB (CD138⁺B220^low) compartments in recipient mice at day 2 after transfer. (D) Heatmap showing the relative expression of B and PC master regulator genes presented as (2^−ΔΔCt) in BM PCs and PBs from both genotypes at day 6 after NP-LPS immunization. Data are presented by applying a column Z score. (E) Number of total ASCs IgM⁺ and NP15-IgM⁺ in the BM assessed by ELIspot at the indicated time points after NP-LPS immunization. Results are from at least 2 representative experiments (A-D,E) or from 2 independent experiments (C) (mean ± SEM, n = 2-9). Mann-Whitney U test was used to assess statistical significance (*P < .05, **P < .01, ***P < .001).