Figure 3: Immunocytochemical characterization of cultured human lung endothelial cells (HL-LECs). (a) and (b): the surface expression of the pan-endothelial marker CD31 and the dot-like cytoplasmic abundance of von Willebrand Factor (vWF) are shown in green by immunofluorescence. (c) and (d): immunoperoxidase detection of lymphatic associated antigens D2-40 and LYVE-1 (brownish) in HL-LEC. (e)–(g): the specific lymphatic lineage commitment of HL-LECs is documented by the nuclear expression of Prox-1 transcription factor (green). Nuclei are counterstained by DAPI in (a), (b), (f) and (g) and by Haematoxylin in (c) and (d). The immunocytochemical analysis was conducted on HL-LECs at passage 4 (P4). Scale bars: (a)–(g) = 25 μm.