FIG. 4.

Macrophages are a potential cellular source of cathepsins in leukocyte-invaded pancreatic islets in NOD mice. A: Immunofluorescence staining reveals F4/80⁺ macrophages close to the sites where peri-islet BM staining is lost (arrows), as shown here by pan-laminin (PLM) staining. The boxed area is shown at higher magnification to the right. Triple-staining for F4/80, as a marker for macrophages, the nuclei marker DAPI and cathepsin C (B), cathepsin S (C), or cathepsin W (D) show colocalization of all three cathepsins, with a subpopulation of macrophages. Scale bars are 100 μm. (A high-quality digital representation of this figure is available in the online issue.)