Immunogold labeling of occludin and caveolin-1 in jejunal enterocytes of 90-min TNF-treated wild-type mice. High pressure–frozen, freeze-substituted, cryoembedded specimens were immunolabeled with antioccludin and anti–caveolin-1, which were detected with 10 nm and 15 nm gold-conjugated secondary antisera, respectively. (A and B) Occludin and caveolin-1 colocalize at tight junctions (TJ) and adherens junctions (AJ). Mv, microvilli. (C and D) The population of vesicles (V) formed after TNF treatment contains occludin and caveolin-1. Single-label images are shown in Fig. S2. Bars, 300 nm.