Visualization of perforin and granzyme B by confocal microscopy. Isolated, ethanol-fixed PMNs were incubated with either mouse IgG or monoclonal antibodies to CD66b, granzyme B, or perforin. Then, Cy3-labeled antibody to mouse IgG was added. The bottom row shows an overview (original magnification × 400); the top row is a zoom (original magnification × 2.4) on selected cells to show details.