Morphology of neutrophils derived from cathepsin G-deficient animals. Bone marrow cells were stained with choracetate esterase (A) or myeloperoxidase stains (B) using conditions recommended by the manufacturer (Sigma). The reddish-pink stain in (A) represents chloracetate esterase activity, and the dark brown stain in (B) represents myeloperoxidase activity. Transmission electron microscopic (TEM) images of bone marrow derived neutrophils are shown in (C). Note that cathepsin G−/− neutrophils have equal numbers of electron-dense granules and normal morphology.