Il7rKO Single Cell

The immune system must distinguish pathogens from innocuous dietary antigens, but the precise mechanisms and cellular actors involved are unclear. Here, we demonstrate that RORt-lineage antigen-presenting cells (APCs) expressing the Autoimmune Regulator (Aire) gene referred to as RORt eTACs are required for oral tolerance. Using lineage tracing and single-cell sequencing, we show that RORt eTACs are of a myeloid-derived lineage and establish consensus identities for all RORt-lineage APCs. We found that RORt eTACs, but not type 3 innate lymphoid cells, are necessary and sufficient for oral tolerance induction. Upon depletion of RORt eTACs, mice fail to develop food-specific Tregs and display severe delayed-type hypersensitivity responses. These findings establish RORt eTACs as critical mediators of oral tolerance and suggest novel targets to modulate immune tolerance. We obtained lymph nodes (mesenteric,cervical, inguinal, axillary, brachial, and para-aortic) from WT and IL7rKO mice and FACS-sorted tdTmt+ MHCII+ cells for subsequent scRNA-seq.