Crosstalk between the microbiota and intestinal dendritic cells in IBD.

Conventional dendritic cells (cDCs) play a pivotal role in orchestrating the delicate balance between immunity and tolerance within the gastrointestinal tract by interacting with other cell types, particularly T cells. Meanwhile, the microbiota is critical for the induction and modulation of the immune system in the gut and plays a key role in the function of cDCs. So far, the study of intestinal cDCs has been encumbered by their limited numbers and phenotypic overlap with other myeloid cells. Recent advancements in single-cell sequencing technology have helped define cDCs and their subsets, while also providing valuable insights into the contribution of cDCs to Inflammatory Bowel Disease (IBD). However, the exact role of cDCs in IBD remains unclear, particularly in terms of how the microbiota influences their function in this context. In this review, we summarize the functions of cDCs in the intestine and during IBD, and the role of the microbiota in cDC biology. We also describe the current limitations in the study of cDCs and the microbiota, as well as new methods for studying DC-T cell communications in vivo, which can help increase our understanding of the function of cDCs in the intestine and develop new therapeutic strategies against IBD.