CX ₃ CR1-Mediated Dendritic Cell Access to the Intestinal Lumen and Bacterial Clearance

TLDR

Dendritic cells and macrophages are essential for innate and adaptive immunity to the intestinal bacterial microbiota. The study identifies a myeloid‑derived mucosal dendritic cell that populates the entire lamina propria of the small intestine. The authors characterize this DC’s distribution throughout the lamina propria in mice. Lamina propria DCs depend on CX3CR1 to form transepithelial dendrites that sample luminal antigens and to clear entero‑invasive pathogens, indicating that CX3CR1‑mediated processes regulate bacterial interactions and may influence tolerance and inflammation.

Abstract

Dendritic cells (DCs) and macrophages are critical to innate and adaptive immunity to the intestinal bacterial microbiota. Here, we identify a myeloid-derived mucosal DC in mice, which populates the entire lamina propria of the small intestine. Lamina propria DCs were found to depend on the chemokine receptor CX3CR1 to form transepithelial dendrites, which enable the cells to directly sample luminal antigens. CX3CR1 was also found to control the clearance of entero-invasive pathogens by DCs. Thus, CX3CR1-dependent processes, which control host interactions of specialized DCs with commensal and pathogenic bacteria, may regulate immunological tolerance and inflammation.