Fig. 3: Intraurothelial macrophages phagocytose neutrophils and UPEC.

a Confocal microscopy demonstrating phagocytosis of GFP⁺ UPEC (green) by F4/80⁺ macrophages (red) in the EpCAM-1⁺ urothelium (white) 1-day post-infection. b GFP⁺  UPEC in the urinary bladder determined by fluorescent image analysis (SCHNELL) after macrophage depletion by intraperitoneal application of αCSF1R antibodies. c The colony forming units of UPEC were determined in bladder homogenates three days post-infection. d Flow cytometry-based quantification of phagocytosis of neutrophils by macrophages (F4/80⁺Ly6G⁺) in bladder digests 1-day post-infection. e Confocal microscopy demonstrating phagocytosis of Ly6G⁺ neutrophils (green) by F4/80⁺ macrophages (red) in the EpCAM-1⁺ urothelium (white) 1-day post-infection. f Density of neutrophils in the urinary bladder after macrophage depletion by intraperitoneal application of αCSF1R antibodies 1-day post-infection. *p < 0.05, ***p < 0.001. Error bars show the mean ± SEM. lu=lumen. The scale bars in a, d indicate 5 µm and the white dashed lines distinguish the EpCAM-1⁺ urothelium from the lumen.