Human gut M cells resemble dendritic cells and present gluten antigen.

Microfold (M) cells are rare intestinal epithelial cells that reside in the follicle-associated epithelium of Peyer's patches(1). M cells transport luminal antigens to submucosal antigen-presenting cells(2,3). These insights primarily derive from transmission electron microscopy and studies using genetically modified mice(2-4). Here we establish an intestinal organoid model to study human M cells and reconstruct the differentiation trajectory of M cells through transcriptome profiling. The results indicate that as well as facilitating luminal antigen transport, human M cells also directly present antigens via the class II major histocompatibility complex (MHC-II). Notably, the related enterocytes only express MHC-II in chronic inflammatory states and do not express typical dendritic cell markers. Human M cells physiologically express a gene profile that resembles that of dendritic cells. Similar to dendritic cells, M cell development is induced by RANKL and CSF2 and requires the transcription factors SPIB and RUNX2. HLA-DQ2.5 M cells process and present gluten antigen as demonstrated in organoid-T cell co-culture assays. These findings suggest that M cells may have a central role in coeliac disease.