Merged images of laser scanning confocal fluorescent microscopy of cornea (CO) and conjunctiva (CJ) sections stained for Fas-ligand (green) with propidium iodide (PI, red) nuclear counterstaining in nonstressed (NS) C57BL/6 mice (B6-NS), desiccating stressed C57BL/6 mice for 5 days (B6-DS5), NS C57BL/6 mice treated with bovine serum albumin (injection control, B6-NS+BSA) or IL-2 subconjunctival injections (B6-NS+IL-2), CD25 knock-out mice (CD25KO-NS). Scale bar = 100 μm 3. B. Laser scanning confocal fluorescent microscopy of human tissue sections (cornea, limbus and conjunctiva) stained for interleukin 2 receptor alpha chain (CD25, green) with PI (red) nuclear counterstaining. For the limbus, the CD25 and CD122 image (in green) is shown besides the merged image with PI nuclear staining. Note absence of staining on the basal epithelial layer of the limbus. Scale bar = 50 μm 3. C. Laser scanning confocal microscopy of human corneal epithelial cells grown on an eight chamber slide and stained for CD25 after treatment with increasing concentrations of MMP-9 for 48 hours. Scale bar = 50 μm 3. D. Representative Western blot showing effect of MMP-9 treatment on CD25 expression by cultured human corneal epithelial cells lysates. Increasing MMP-9 concentration decreased CD25 levels.