Anti cytokeratin 18

hAECs were fixed with 4% paraformaldehyde for 20 minutes at room temperature and then washed twice (5 minutes each) with PBS. Cells were permeabilized with 0.1% Triton X-100 for 10 minutes at room temperature and then washed twice with 1 × PBS. Then cells were blocked with blocking solution for 30 minutes and incubated overnight at 4°C with anti-Cytokeratin 18 (mouse anti-human 1 : 200, Boster, Wuhan, China), anti-CD34 antibody (rabbit anti-human 1 : 100, Abcam, Cambridge, MA, USA), and anti-Vimentin (rabbit anti-human 1 : 100, Cell Signaling Technology, Danvers, MA, USA). Washed three times with PBS, the cells were probed with FITC-labeled IgG (1 : 200, Santa Cruz, CA, USA) or Rhodamine- (TRITC-) labeled IgG (1 : 100, Invitrogen, CA, USA). Fluorescence images were obtained with a Leica DMI3000 microscope (Heidelberg, Germany).