Fig. 1.

Flagellin inhibits the formation of cilia. a The ultrastructure of the inner surface of a bronchosphere embedded 30 days after seeding (23.000-fold magnification). Arrows indicate kinocilia and * indicate microvilli. b Representative H&E staining of a bronchosphere embedded 30 days after seeding. Scale bar: 20 μm. Arrows indicate cilia. (c to f) Developing bronchospheres were treated with different PAMPs during the differentiation phase starting at day 2 after seeding. Cilia beating (c), the presence of lumina (d), and diameter (e) were determined under the phase contrast microscope 14, 22, and 30 days after seeding. (f) Representative H&E staining of bronchosphere cultured under the indicated conditions embedded 30 days after seeding. Arrows indicate cilia. Scale bar: 20 μm. The percentage of bronchospheres with cilia (g) and lumina (h) were analyzed H&E-stained sections. Data were compared by unpaired Student’s t-test and are shown as the mean ± SEM from three independent experiments. *p < 0.05, **p < 0.01. (i) H&E staining of bronchospheres cultured under the indicated conditions embedded 14 and 21 days after seeding. Arrows indicate cilia. Scale bar: 20 μm