Apoptotic cells are rapidly cleared by tissue-resident phagocytic cells. In Nature, Cummings et al. show that apoptotic mouse intestinal epithelial cells in the lamina propria of the small intestine are sampled by CD11b−CD103+ dendritic cells (DCs) and two subsets of macrophages, CD11b+CD103+ and CD11b+, a process that induces subset-specific anti-inflammatory signatures in the sampling cells. The authors use a transgene encoding the diphtheria toxin receptor fused to enhanced green fluorescent protein (eGFP) driven by the villin promoter to induce apoptosis in conditions that do not trigger inflammation. Following phagocytosis of apoptotic cells, tracked via the acquisition of GFP, both DCs and macrophages downregulate genes encoding pro-inflammatory products and upregulate genes encoding negative regulators of inflammation, in a pattern unique to each subset. The CD103+ DCs are the only subset to upregulate genes encoding products required for instruction of a regulatory T cell program and to travel to the mesenteric lymph nodes to induce the differentiation of regulatory T cells.

Nature (9 November 2016) http://dx.doi.org/10.1038/nature20138