Expression of GzmA in human PMNs. (A) PMNs of 5 different donors were intracellularly stained with antihuman GzmA (black profile) and the respective isotype control (white profile). A representative histogram is shown. (B) Western blotting revealed a strong band between 29 and 35 kDa in PMNs and peripheral blood mononuclear cells (PBMCs), which served as a positive control, typically for GzmA. The blot was reblotted with a mouse antihuman beta-actin antibody to demonstrate that comparable amounts of protein were used. Lanes a through d show human PMNs of 4 different donors, and lane e shows human PBMCs. (C) RT-PCR was performed as described above. Lane a shows human PBMCs as positive control; lanes b through e, PMNs from 5 different donors; and lane f, negative control. M indicates length marker.