Staining of eosinophils from the BAL fluid of wild-type (+/+) and eotaxin null (−/−) mice. Lung lavage was performed at 18 hours after OVA aerosol challenge and the cells were stained by Diff-Quick staining after cytospin. Representative pictures are shown for each genotype in lower (upper panel) and higher (lower panel) magnification. Arrowheads indicate eosinophils.