Fig. 5
Contribution of IL-21R signaling to the expansion and differentiation of dual-κ B cells. a Representative analysis of single and dual-κ B cells in FO and MZ subsets of wt and IL-21R KO MRL/lpr-Igkm/h mice. Cell subsets were gated as shown in Supplementary Fig. 6a. b Mean frequencies of dual-κ B cells in FO or MZ κ+ subsets described in a. Data are combined from five independent experiments with N = 15 wt and 14 KO mice. c Mean frequency of dual-κ cells within CD3–CD19+CD21–/lowCD24high splenic immature/transitional B cells (gated as in Supplementary Fig. 4a, SP), combined from two independent experiments (N = 7 for both wt and IL-21R KO MRL/lpr-Igkm/h mice). d Analysis of CD138+CD44high single and dual-κ plasmablasts (PBs, gated as in Supplementary Fig. 7a) from splenocytes of wt and IL-21R KO MRL/lpr-Igkm/h mice. e Mean frequency of dual-κ cells within the PB cell subset described in (d). Data are combined from five independent experiments with N = 15 wt and 14 KO mice. f EdU incorporation by splenic single-κ (open bar) or dual-κ (filled bar) CD3–B220+ B cells (gated as in Supplementary Fig. 1a, c), 24 h after EdU injection in 12–17-wk-old wt or IL-21R KO MRL/lpr-Igkm/h mice (N = 3, in one experiment). g Analysis of CD138–IgG+ (IgG1,IgG2a/2b) single or dual-κ memory B cells (gated as in Supplementary Fig. 7c) in spleen of wt and IL-21R KO MRL/lpr-Igkm/h mice. h Frequency of dual-κ cells within the memory IgG+ B cell subset shown in g. Data are combined from three independent experiments with N = 6 wt and 7 KO mice. i Fold change of dual-κ B cell frequencies in PBs and IgG+ cell subsets of wt and IL-21R KO MRL/lpr-Igkm/h mice relative to those in their respective FO B cell subset, based on data in panels (b–e–h). Data in panels (b, c, h, i) were from 15–20-wk-old wt or IL-21R KO MRL/lpr-Igkm/h mice. *P < 0.05, **P < 0.01, ***P < 0.001; n.s. not significant. Significance was assessed by Student’s t- or Mann–Whitney tests. In all bar graphs the standard error bars represent SEM and each symbol represents an individual mouse
