Resident immune cells in the healthy kidney. (A) Schematic representation of the distinct developmental waves contributing to renal F4/80^hi cells. Kidneys from newborn mice contain a prominent population of yolk sac–derived macrophages that exhibit an F4/80^hiCD11b^low surface phenotype but lack MHC-II expression. Within a few weeks after birth these cells are replaced by phenotypically similar cells that can be distinguished by MHC-II expression of an unspecified haematopoietic stem cell origin. With time MHCII⁺F4/80^hiCD11b^low cells acquire signs of Clec9a-Cre expression history (yellow highlight), indicating that they arise from dendritic cell progenitors. (B) Spatial distribution of dendritic cell subsets in the steady-state adult kidney. cDC1 shows a preferential localization to the outer cortex. cDC2 and CD64⁺CD11b^hi dendritic cells are located preferentially at the border of the cortex and medulla. MHCII⁺F4/80^hiCD11b^low (CD64⁺F4/80^hi) cells are found in the cortex and medulla, but are the only dendritic cell subtype found in the steady-state medulla.