2.5. Nasal Lavage Fluid (NALF) Collection and Cell Counting

After the final challenge, NALF was immediately collected from the sacrificed mice via cannulation from the upper trachea in the nasal cavity direction followed by gentle washing with 10 mL of ice-cold PBS. The total cell numbers in the NALF were counted using a cell counter (Thermo Fisher Scientific, Waltham, MA, USA). Differential eosinophils in each group were centrifuged using a Hanil Cytospin (Seoul, Korea). The slides were stained with Diff-Quik staining reagent (Sysmex, Chuo-ku, Kobe, Japan) according to the manufacturer’s instructions and compared under a light microscope (Olympus Corporation, Tokyo, Japan) at 400× magnification.