Immunologic cells invade within the FSGS-BALB/c glomeruli at 5 weeks. (A) Because CD45 reacts with not only leukocytes but also, endothelial cells, we counted only CD31(−)/CD45(+) cells to exclude endothelial cells. The number of CD31(−)/CD45(+) cells was highest in the Muse group among the four groups. (B) The number of F4/80(+) macrophages was also highest in the Muse group. ***P<0.001. (C–E) Localization of (C) CD45 (leukocytes)/GFP (Muse or non-Muse cells), (D) CD45 (leukocytes)/CD31 (endothelial) double staining on the same section, and (E) F4/80 (macrophages)/GFP (Muse or non-Muse cells). In D, most of CD45 did not merge with CD31. In the Muse group, the distribution of F4/80(+) cells in most of the glomeruli was similar to that of CD45 shown in C and D. As shown in E, however, a very small number of glomeruli showed invasion of F4/80(+) cells. Note that arrowheads in E show the GFP(+) fragments/particles in F4/80 cytoplasm, suggesting phagocytosis of GFP(+) fragments/particles by F4/80(+) macrophages. Scale bars, 20 μm.