LNs are permissive sites for kidney organogenesis. (A): Schematic view of embryonic kidney transplantation into the jejunal LN. (B): Hematoxylin and eosin-stained section of donor embryonic kidney showing SSBs (upper left panel); whole-mount LN 3 weeks after embryonic kidney fragment transplantation (upper right panel); and sectional view of the same LN after staining with ER-TR7 (red), with the presence of GFP+ (green) donor cells. Nuclei were counterstained using Hoechst (blue) (lower left panel). The boxed area is shown enlarged (lower right panel). (C): Detail of 3-week kidney graft showing variable glomerular maturity (upper panel). Enlarged views of the boxed regions are shown upon CIV staining (red). Nuclei were counterstained using Hoechst (blue) (lower panels). (D): Merged images of GFP (green); CD31, Pdpl, Cldn-2, CK8, or EPO (red); and Hoechst (blue) staining on sections of a 3-week kidney graft. Abbreviations: CIV, collagen IV; CK8, cytokeratin-8; Cldn-2, claudin-2; EPO, erythropoietin; ER-TR7, reticular fibroblasts and reticular fibers; GFP, green fluorescent protein; LN, lymph node; Pdpl, podoplanin; SSBs, S-shaped bodies; wks, weeks.