Figure 1.

Human alveolar type II cells cultured at an air–liquid interface (A/L). Human alveolar type II cells were cultured under A/L conditions, as described for infection with SARS-CoV. (A) Phase micrograph of the epithelial monolayer with inclusions (lamellar bodies), indicated by arrows, clearly visible within the cytoplasm of type II cells. (B) The effect of A/L culture conditions and treatment with IL-4 and IL-13 on selected proteins by immunoblotting. Lane 1 is a extract of freshly isolated type II cells, lane 2 is empty, lanes 3 and 4 contain cells cultured under A/L conditions with KIAD alone, lanes 5 and 6 contain cells cultured under A/L conditions with KIAD, IL-4, and IL-13, lanes 7 and 8 contain cells cultured under submerged conditions with KIAD, and lanes 9 and 10 contain cells cultured under submerged conditions with KIAD, IL-4, and IL-13. A/L conditions increased the expression of angiotensin-converting enzyme–2 (ACE2), surfactant protein (SP)–A, proSP-B, proSP-C, and ATP-binding cassette sub-family A member 3 (ABCA3), but not fatty acid synthase (FAS). IL-4 and IL-13 significantly increased the expression of ACE2. GAPDH, glyceraldehyde 3–phosphate dehydrogenase.