Characterization of the TGF-α–positive granules in neutrophils from peripheral blood by double-labeling. (a) TGF-α (large arrows) does not colocalize with lactoferrin (Lf ) (small arrows), a marker of neutrophil specific granules. (b) No colocalization with gelatinase (Gel), a marker of gelatinase-granules. (c) TGF-α (large arrow) is detected in a compartment other than cathepsin G (Cth) (small arrows), which is present in azurophil granules. (d) TGF-α (large arrow) is detected in a compartment other than albumin (Alb) (small arrows) of secretory vesicles. Bars = 200 nm.