Dendritic cells administered intrarectally penetrate the intestinal barrier to break intestinal tolerance via Th2-medeiated colitis in mice

Intestinal lamina propria dendritic cells (LPDCs) in mice are known to extend dendrites between the intestinal epithelia and the luminal side when processing luminal antigens. We conducted intrarectal cell transfer experiments of bone marrow-derived dendritic cells (BMDCs) in mice to assess dendritic cell penetration of the intestine. Intrarectally administered GFP⁺ BMDCs localized in the colonic LP within 3h and the spleen within 12h after administration. 72h after administration, recipient C57BL/6 mice showed acute diarrhea, and administration of BMDCs (once weekly for 3 weeks) induced intestinal inflammation with increased numbers of recipient macrophages and CD4⁺ T cells exhibiting a Th2-mediated immune response. These results demonstrate that DCs actively communicate across the intestinal barrier, and highlight a potential technique for controlling colonic immune tolerance.