Subcellular localization of HBP by electron microscopy.

Neutrophils were fixed and prepared for transmission electron microscopy as described in “Materials and methods.” (A) Neutrophils were immunostained with a monoclonal antibody against ALP and a rabbit polyclonal antibody against HBP. Bound antibody was detected with gold-labeled secondary antibodies against mouse IgG (6-nm gold particles) and rabbit IgG (10-nm gold particles), respectively. Arrows indicate HBP, arrowheads indicate ALP. (inset) Secretory vesicle containing HBP at a higher magnification. (B) Neutrophils were immunostained with a monoclonal antibody against MPO and a polyclonal antibody against HBP, as described above. Arrows indicate HBP, arrowheads indicate MPO. (inset) Azurophil granule containing HBP at a higher magnification. Images are representative of 4 separate experiments. Bar = 200 nm.