Fig. 1: hAELVi cell air–liquid-interface cultures as model of the distal lung.

a Schematic representation of hAELVi air–liquid-interface (ALI) cultures. b Measurement of transepithelial electrical resistance (TEER) and permeability of sodium fluorescein across the cellular monolayer of hAELVi cells growing under ALI up to 28 days. Experiments were performed for five (TEER) or four (Papp) independent experiments in technical duplicates, respectively. c Electron microscopic analysis of hAELVi cells grown at the ALI for 0 or 21 days. Data are representative for two independent experiments. Bar: 20 μm. d Western Blot analysis of ACE2 expression of hAELVi cells grown under ALI for 0, 7, 14, 21, or 28 days, respectively. Data are representative for three independent experiments. e Detection of ACE2, DPP4, and TMPRSS2 in cell lysates of hAELVi cells grown under ALI for 0, 7, 14, 21, or 28 days, respectively, using ELISA. Experiments were performed for two independent experiments in technical duplicates.