Benoit Chassaing, Nathalie Rolhion, Amélie de Vallée, Sa’ad Y. Salim, Maelle Prorok-Hamon, Christel Neut, Barry J. Campbell, Johan D. Söderholm, Jean-Pierre Hugot, Jean-Frédéric Colombel, Arlette Darfeuille-Michaud
(A) Interaction of bacteria with murine PPs placed in Ussing chambers after a 4-hour infection period, with or without anti-GP2 antibody (1 μg/ml) and with or without 0.5% methyl α-d-mannopyranoside (mann). When needed, PPs were preincubated with anti-GP2 antibody. (B) Confocal analysis of PP sections after labeling of AIEC LF82 with LPS O83 antibody (green), of M cells with anti-GP2 antibody (red), and DNA with Hoechst (blue). Scale bars: 20 μm. Arrowheads show clear colocalization of bacteria and M cells. (C) Interaction of wild-type LF82 and lpf mutant with murine PPs placed in Ussing chambers after a 4-hour infection period. (D) HES staining and confocal analysis of indicated areas after Cy3-EUB228 FISH staining to detect bacteria (red) and Hoechst to identify DNA (blue). Scale bars: 100 μm for HES staining and 20 μm for confocal analysis. Images in the bottom row correspond to the boxed regions in the top row. (E) In vivo interaction of wild-type LF82 and lpf mutant with murine PPs using ileal loop assay after a 4-hour infection period in the presence of 0.5% methyl α-d-mannopyranoside. (F) Interaction of wild-type LF82 and lpf mutant with murine small intestine mucosa without PPs after a 4-hour infection period in Ussing chambers. All results are expressed as numbers of mucosa-associated bacteria; each value is the mean ± SEM of at least 5 separate experiments. (G) Interaction of wild-type LF82 bacteria with murine PPs placed in Ussing chambers and coincubated with nonpathogenic MG1655 E. coli K-12 strain expressing or not expressing LPFLF82. *P < 0.05, **P < 0.01, ***P < 0.001.