Figure 4
IFN-gamma stimulation. Image (A,B) show immunofluorescence staining of quiescent UC (Mayo score ≤ 2) in colonic biopsies for IL-33 (red) and pSTAT1 (green) and nuclei counterstained with Hoechst (blue). Image (A) shows a strong pSTAT1 signal in epithelial cells following 24 h of IFN-gamma 100 ng/ml stimulation for 24 h. Infelt to the left is an isotype and concentration matched control. Image (B) shows the control biopsy cultured in basal medium for 24 h (non-stimulated) with no pSTAT1 epithelial signal. Immunoenzymatic staining for IL-33 (brown) is shown in a healthy control (C,D), Baseline biopsy at 0 h (image C) and following 24 h of IFN-gamma stimulation (image D) Further pSTAT1 (brown) staining is shown in image E after 24 h 100 ng/ml IFN-gamma stimulation. Acute UC (Mayo score = 6) is shown in (F–H). IL-33(brown) is shown in image (F) (baseline 0 h) and image (G) (stimulated 24 h with IFN-gamma). Image (H) shows pSTAT1(brown) following IFN-gamma- stimulation for 24 h. Quantification of immunostaining is given in graphs (I–L). Healthy controls = NC. No significant presence of IL-33 was seen in the epithelium following IFN-gamma stimulation for 24 h. pSTAT1 was significantly increased in the epithelial border and stroma in both healthy controls (NC) and UC. Scale bars are given at 20 μm.
