In-depth comparison of human serous cavity resident macrophages and dendritic cells to their murine counterparts

In murine peritoneal and other serous cavities, Gata6 drives identity of the major resident cavity macrophage population, with a smaller subset of cavity macrophages dependent upon Irf4. Here we show that Gata6+ macrophages in the human peritoneum are rare, regardless of age. Instead, many aligned with CD206+LYVE1+ mouse cavity macrophages from a differentiation stage just preceding expression of Gata6. The comparatively low abundance of CD206+ converting macrophages in healthy C57BL/6J mice was sustained after high-fat diet feeding or in mice capture from the wild, suggesting that the major resident macrophages between the species share overlapping differentiation programs but differing predispositions to distinct differentiation stages. Irf4-dependent mouse serous cavity macrophages aligned closely with CD1c+CD14+CD64+ human peritoneal dendritic cells (DCs) that, in turn, resembled CD1c+CD14-CD64- peritoneal cDC2. Peritoneal DC1 and plasmacytoid DCs were rare in both species. This cross-species resource comparing mouse and human serous cavity immune cells will facilitate translational research.