Fig. 1

Splenic dual-κ B cells display higher proliferation rates than single-κ B cells. a Representative flow cytometric contour plots showing frequency of Ki67⁺ single and dual-κ cells within B220⁺CD19⁺ CD138^– B cells (top) and CD138⁺CD44^high plasmablasts (PBs, bottom), gated as shown in Fig. S1a, b. b Mean frequency of Ki67⁺ cells within single (white bar) or dual-κ (black bar) B cells and PBs described in a. Data are combined from three independent experiments using 9–16-wk-old MRL/lpr-Igk^m/h mice (N = 15 total). c Representative contour plots showing the frequency of EdU⁺ single and dual-κ cells within CD3^–B220⁺ B cells (gated as in Supplementary Fig. 1a–c) 24 h after either EdU (top row) or PBS (bottom row) injection in MRL/lpr-Igk^m/h mice. d Mean frequency of EdU incorporation by splenic single-κ (white bar) or dual-κ (black bar) B cells (gated as described in c), after EdU injection in 12–14-wk-old MRL/lpr-Igk^m/h mice. Data from one untreated MRL/lpr-Igk^m/h mouse indicate EdU background staining in total Igκ⁺ B cells. Representative data from one out of three experiments is shown with N = 4 in each experiment. e Representative flow cytometric analysis to measure the frequency of c-Myc-positive cells within splenic CD3^–B220⁺ single-κ (middle panel) or dual-κ B cells (far right panel), gated as shown in Supplementary Fig. 1a–d. Far left panel shows Igκ⁺ B cells stained with an isotype control. f Mean frequency of c-Myc⁺ cells within single or dual-κ B cell subsets described in e in 13-wk-old MRL/lpr-Igk^m/h mice. N = 4 from one experiment. *P < 0.05, ****P < 0.0001; 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 an individual mouse