Fig. 6

HIF-1α deficiency in B cells exacerbates collagen-induced arthritis. a Arthritis incidence in Mb1^creHif1a^f/f (n = 9) and WT mice (n = 9) after collagen immunization. NI non-immunized mice; CIA collagen immunized mice. b Clinical score of arthritis in mice as described in a. c Picture and quantification of paw thickness at day 45 after the first immunization in mice as described in a. Scale bar, 2 mm. d Histopathology sections and quantifications of erosion area (H&E), inflammation area (H&E), and osteoclast number (TRAP) in paw from mice as in a. Arrows indicate erosion or inflammation area. Scale bars, 500 μm. e Quantitative RT-PCR analysis of Tnf, Ifng, Il17a, Il1b, and Il10 mRNA expression in knee synovial tissue from mice as described in a. f IL-17, IFN-γ, IL-10, and TGF-β expression by splenocytes isolated from Mb1^creHif1a^f/f (n = 9) and WT mice (n = 9) after collagen immunization followed by in vitro re-stimulation with collagen (20 μg/ml) for 48 h. g IL-10, TGF-β, and IL-35 production by enriched splenic B cells isolated from Mb1^creHif1a^f/f (n = 6) and WT mice (n = 6) after collagen immunization followed by in vitro re-stimulation with collagen (20 μg/ml) for 48 h. h, i Representative plots and quantification of IL-17A⁺CD4⁺(Th17), IFN-γ⁺CD4⁺(Th1), CD25⁺Foxp3⁺CD4⁺(Treg), IL-10⁺CD4⁺(Tr1), and IL-10⁺CD19⁺(IL-10⁺B) cells in spleen (h) and draining lymph nodes (dLNs) (i) from Mb1^creHif1a^f/f (n = 7) and WT mice (n = 7) after collagen immunization. j Representative plots and percentage of IL-23R⁺IL-17A⁺CD4⁺ and GM-CSF⁺IL-17A⁺CD4⁺T cells in spleen and dLNs from Mb1^creHif1a^f/f (n = 6) and WT mice (n = 6) after collagen immunization. Data are shown as mean ± s.e.m. Pictures are representative of three independent experiments. NS not significant; *P < 0.05, **P < 0.01, and ***P < 0.001 (Kaplan–Meier analysis with log–rank test (a) or two-tailed unpaired Student’s t-test (b–h)) (see also Supplementary Figure 6)