CSF2 and inflammatory bowel disease: Such proper maturation and activation of iDCs has been shown to initiate subsequent T cell‐driven inflammatory responses in the onset of IBD.[112] We also observed that LPS alone was sufficient to induce an elevated level of GM‐CSF in IEB model‐MF co‐cultures (Figure 6b‐ii), suggesting that, besides iDCs, MFs were also capable of actively sampling the apical content.[113] Videos S2 and S3 (Supporting Information) show that activated (NF‐κB+) iDCs and MFs were detected in the immediate vicinity of the IEC layer.