Figure 1.

Efficiency of dNP2 protein delivery into lung cells by intranasal administration. (a–c) Eight-week-old BALB/c mice were intranasally administered 120 μg of German cockroach extract (GCE) or phosphate-buffered saline (PBS) twice per week for 3 weeks. On day 21, 100 μg of dTomato, Hph-1-dTomato, dNP2-dTomato, or PBS was intranasally administered. After 15 min, bronchoalveolar lavage (BAL) was performed twice for each mouse with 1 ml of PBS. The lungs were harvested and prepared as frozen blocks. (b) The tissues were sectioned to 8 μm thick and observed by fluorescence microscopy after nuclear staining using Hoechst. A representative image of three independent experiments is shown. (c) BAL fluid was collected, and intracellular fluorescence of the BAL cells was analyzed by flow cytometry. Histograms of red fluorescence and mean fluorescence intensities (MFIs) of the indicated populations are shown.