Figure 1: Histological sections and cultures of adenoid epithelium. Histological sections of adenoid epithelium and cultures of secretory cells. (a) Histological section of adenoid epithelium (0.5 μm thick) processed to visualize intracellular sugars using a PAS method. The arrow shows the presence of PAS positive secretory material inside the cytoplasm. (b) Confocal microscopy of adenoid epithelium slides showing positive immunoreactivity for the antibody MAN5AC (green). Cell nucleus was counterstained with propidium iodide. (c) A phase contrast microscopy showing secretory cells culture after 21 days of cell growth, with plenty of secreted material attached to the cell surface over time (arrows). (d) A confocal microscopy of secretory cells showing positive immunoreactivity for MUC5AC (green) and MUC5B (red). The image corresponds to the overlapping of the two fluorescent signals. Abundant immunoreactive granular material is observed inside the cell. These observations indicate that cell culture conditions allowed for the development of cultures enriched in secretory cells from the respiratory epithelium. Bar in (a)–(c) = 20 μm and (d) = 5 μm.