Antigen-induced neutrophilic airway inflammation in OTII mice. OTII mice were challenged with 50 μg of OVA (B-D) or PBS (A) intranasally for 3 days (once per day). Lung histology was performed in hematoxylin- and eosin-stained sections of formalin-fixed, paraffin-embedded tissues of mice that were killed 24 hours after the last OVA or PBS inhalation. Scale bars in photomicrographs and insets are 100 and 20 μm, respectively. Arrowheads indicate neutrophils; E, bronchiolar epithelium; asterisk, representative areas of peribronchiolar or perivascular inflammation; and area of section shown at higher magnification in the inset. Images were captured with a Nikon E1000M microscope (Nikon, Melville, NY) utilizing a 20×/0.75 NA objective and a 60×/0.95 objective for inserts (ocular eyepieces, 10×), a SPOT FLEX camera (Diagnostic Instruments, Sterling, MI) model 15.2, SPOT Advanced 4.5 software (Diagnostic Instruments), and Photoshop CS2 (Adobe Systems, San Jose, CA).