Ultrastructural localization of gzmA in 1.3E6SN but not in B6 neutrophils and eosinophils by immunogold electron microscopy. (A) Cryosections of 1.3E6SN cells or of in vitro-generated (BM cells, day 9, G-CSF) B6 neutrophils or eosinophils were fixed, immunogold-labeled with αmgzmA mAb (7.1; arrows) and subsequently analyzed by electron microscopy. (B) Western blot (WB) analysis of lysates of MACS-sorted CD8⁺ LCMV-immune cells from B6, gzmA^-/-, and gzmB^-/- mice (5 × 10⁵ cell equivalents/lane) and of purified gzmA protein (50 ng) using either αmgzmA mAb (7.1, 1:20) or αmβ-actin mAb (C-11, 1:1000) and peroxidase-labeled secondary antibody (1:10 000). Molecular weight was as follows: gzmA, 60 kDa; β-actin, 43 kDa.