Induced regulatory T cells (iTregs) +anti‐interleukin‐12p40 (IL‐12p40), generated from CD4+ Foxp3– cells from mice sensitized to sheep globulin (SG), enhanced renal injury in a model of mild rapidly progressive glomerular nephritis (RPGN). Ly5.1 congenic mice were sensitized subcutaneously to 0.5mg SG/Freund's complete adjuvant and given medium (n = 8) or 10 × 106
iTregs+anti‐IL‐12p40 cultured from CD4+ Foxp3– cells from SG‐immunized Foxp3‐GFP mice (n = 9). Intravenous sheep anti‐mouse glomerular basement membrane (GBM) globulin (5 mg) was administered 4 days later, before mice were killed after a further 10 days. Renal injury was assessed by (a) serum urea (dotted line represents non‐nephritic wild‐type (WT) mice; n = 4), (b) urine protein/creatinine ratio, (c) percentage of glomeruli with segmental necrosis and (d) interstitial injury score. Immunohistochemical staining on periodate lysine paraformaldehyde‐fixed frozen kidney sections was performed to quantify (e) CD4+ cells, (f) macrophages and (g) neutrophils within glomeruli and (h) CD4+ cells, (i) macrophages and (j) neutrophils within the cortical interstitium. EliSpot measurement of (k) IFN‐γ
+ and (l) IL‐17A+ spots/1 × 106 stimulated splenocytes. (m) Serum mouse anti‐sheep IgG titres. *P < 0·05. c/gcs, cells per glomerular cross section; c/hpf, cells per high‐power field.