Lm-containing vacuole transfer across the intestinal barrier. (A) Intestinal tissue of iFABP-hEcad transgenic mice was infected with 109 Lm for 45 min, fixed, and stained for F-actin, Ecad cytoplasmic domain (cyto dom), and Lm. XZ and YZ show sections at selected positions. (B) Optical sections of infected intestinal villi of mtd Tomato mouse stained for Lm and nuclei and with WGA. (a) Lm (arrowheads) interacting with and entering an enterocyte. (b and c) Lm (arrowheads, insets) inside an enterocyte and associated with membrane (red). (d) Lm (open arrowheads, bottom insets) in the lamina propria and not associated with membrane and another Lm (closed arrowheads, top insets) inside an enterocyte and associated with membrane (red). (C) TEM sections of TAT-NSF–treated and 45-min Lm-inoculated ligated loop. (left) Intracellular Lm located below the cell nucleus and close to the cell membrane (dashed black line) of an IEC. (top right) Higher magnification of main panel. Intracytosolic Lm is located close to the basal cell membrane (dashed black line). (bottom right) Higher magnification of top right panel (boxed area). Intracytosolic Lm is enclosed in a membrane vacuole. Pictures are representative of two mice. Bars: (A and B) 10 µm; (C, left) 5 µm; (C, top right) 2 µm; (C, bottom right) 200 nm.
