Figure 2

L. rhamnosus MV are internalized within 2 h by intestinal epithelial cells. (a–c) Approx. 3 × 10¹⁰ CFSE-labelled JB-1 MV or EcN OMV were incubated at 37 °C for 2 h with HT-29 cells (a) or MODE-K cells (b,c), and cell-associated fluorescence was measured by flow cytometry (left) or fluorescence microscopy (right). (c) Representative z-stack demonstrating CFSE fluorescence adjacent to a MODE-K nucleus after incubation with CFSE-labelled JB-1 MV. Crosshairs represent the reconstructed slices shown on the upper and right side of the image, while lines through the slices represent the z-plane shown in the main image. (d,e) Approx. 3 × 10¹⁰ CFSE-labelled JB-1 MV or phosphate-buffered saline (PBS) vehicle were orally gavaged to BALC/c mice, then 2 h later jejuna were isolated, and fluorescence was measured by flow cytometry of (d) A33⁺ CD45^- intestinal epithelial cells or (e) CD11c⁺ MHC II⁺ lamina propria dendritic cells. Scale bars represent 10 μm. Green colour represents CFSE signal, while blue represents nuclear stain (Hoechst 33342).