Fig. 6. Comparable ultrastructural localization of LYVE-1 in intestinal lymphatic vessels of wild-type and T1α/podoplanin–/– mice. (A) High levels of immuno-nanogold labeling for LYVE-1 were detected at both the luminal (L) and the abluminal plasma membrane of lymphatic endothelium in the ileum of newborn wild-type mice. Some labeling of the lateral plasma membranes was also observed, whereas LYVE-1 was absent from the cytoplasm. (B) LYVE-1 expression was absent from blood vascular endothelium. (C and D) Lymphatic endothelial cells in the intestine of T1α/podoplanin–/– mice also had high levels of LYVE-1 immuno-nanogold labeling of the luminal and abluminal plasma membranes. The lateral plasma membranes were also labeled, with the exception of punctate contact areas between adjacent cells (A, C and D, arrows). (E and F) Replacement of the primary LYVE-1 antibody with an unrelated rabbit IgG control resulted in the absence of lymphatic endothelial cell labeling in the ileum of wild-type (E) and of T1α/podoplanin-null mice (F). Bars for (A), (C), (D) and (E) = 0.5 µm, (B) and (F) = 0.4 µm.