Fig. 8

Schematic representation of the air–liquid interface (ALI) culture model of IL-4-human nasal epithelial cells, administration of BCI-121 and coculture with naïve CD4 + T cells. Primary human nasal epithelial cells were seeded onto Transwell membranes and allowed to grow to confluence for 4–7 days. Cells were exposed to air at the apical side (air–liquid interface; ALI) and stimulated for approximately 2–3 weeks at the basal side with medium (containing high concentrations of retinoic acid to induce mucociliary differentiation). To establish IL-4-treated human nasal epithelial cells, IL-4 was added to the basal medium upon the first exposure of the cells to air, and the medium with or without IL-4 was refreshed every 2 days for approximately 2–3 weeks (A). Then, when the nasal epithelial cells had differentiated, naïve CD4 + T cells were added to the basal medium with refreshment of IL-4-free medium and BCI-121-free medium (B)