Comparison of splenic and small intestine lamina propria macrophages

The intestinal immune system must elicit robust immunity against harmful pathogens but restrain immune responses directed against commensal microbes and dietary antigens. The mechanisms that maintain this dichotomy are poorly understood. Here we describe a population of CD11b+F4/80+CD11c macrophages in the lamina propria (LP) that express several anti-inflammatory molecules including interleukin 10 (IL-10), but little or no pro-inflammatory cytokines, even upon stimulation with Toll-like receptor (TLR) ligands. These macrophages induced, in a manner dependent on IL-10, retinoic acid and exogenous transforming growth factor-, differentiation of FoxP3+ regulatory T cells. In contrast, LP CD11b+ dendritic cells elicited IL-17 production. This IL-17 production was suppressed by LP macrophages, indicating that a dynamic interplay between these subsets may influence the balance between immune activation and tolerance.

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Denning TL, Wang YC, Patel SR, Williams IR, Pulendran B