Fig. 6

Intestinal immune performance in response to colonization with Bacteroides caecicola and Bacteroides uniformis. A Concentration of IgA in duodenal contents (n = 12). B and C Gene expression levels of IgA and PIgR in duodenum (n = 12). D Distribution of IgA (red) in duodenal tissues (blue). Scale bars, 200 μm. E Flow cytometric analysis the proportion of IgA-coated bacteria in duodenal contents, the IgA⁺ gates were determined follows negative control (n = 6). F Confocal images showed the tissues (blue), MHC II (red) and FISH probes EUB388-FAM targeted total bacteria (green) in duodenum, scale bars, 50 μm. G–L Gene expression levels of in duodenum (n = 12). Data are means ± SEM; unpaired Student’s t test; β-actin and HMBS were used as the endogenous control for qPCR; * P < 0.05, ** P < 0.01, *** P < 0.001