Figure 2.

Intestinal epithelial cells in microbial homeostasis. The microbiota and microbiota-derived immune stimuli are shown in red. IECs, which are the communicators between microbiota and professional immune cells, and IEC-mediated effects are shown in yellow. Immune cells and their influence on epithelial barrier formation and IgA-mediated mucosal host protection are shown in blue. Please refer to the text for details. AMP, antimicrobial peptide; IEC, intestinal epithelial cell,; LPS, lipopolysaccharide; PSA, polysaccharide A; TGF-β, transforming growth factor beta; TNF, tumour necrosis factor; TSLP, thymic stromal lymophopoietin; MIP2, macrophage inflammatory protein 2.