Figure 4. In vivo anti–IL-1β treatment decreases Il1rn^–/– Treg osteoclastogenic potential and bone erosion.

(A–C) RANKL expression on Foxp3^eGFP+ T cells from lymph node (LN) by flow cytometry (n = 5 per group). MFI, mean fluorescence intensity. (D–F) RANKL expression on Foxp3^eGFP+ T cells from synovial tissue by flow cytometry (n = 5 per group). (G and H) Sorted Tregs from WT (n = 4) and Il1rn^–/– treated with anti–IL-1β (n = 5 per group) or Ig control (n = 7) were cocultured with macrophage precursor cells; after 5 days of coculture, cells were stained for tartrate-resistant acid phosphatase (TRAP) and TRAP⁺ multinucleated cells were counted. Scale bars: 1 mm. (H) Number of TRAP⁺ osteoclasts. (I–K) Sorted RANKL^hi and RANKL^lo Foxp3^eGFP+ Tregs from Il1rn^–/– mice were cocultured with macrophage precursor cells; after 5 days of coculture, TRAP⁺ multinucleated cells were measured (surface area) and counted (n = 8 per group). Scale bars: 1 mm. Data are expressed as mean ± SEM. Statistical significance was determined using Mann-Whitney U test (B and D) or 1-way ANOVA (F and H).