Granzyme B Activity in Target Cells Detects Attack by Cytotoxic Lymphocytes

摘要: Lymphocyte-mediated cytotoxicity via granule exocytosis operates by the perforin-mediated transfer of granzymes from CTLs and NK cells into target where caspase activation other death pathways are triggered. Granzyme B (GzB) is a major cytotoxic effector in this pathway, its fate has been studied several groups using immunodetection. In study, we have used newly developed cell-permeable fluorogenic GzB substrate to measure protease activity three different living targets following contact with effectors. Although no measurable CTL or NK92 cells, rapidly becomes detectable throughout cytoplasm after effector-target engagement. We combined second selective for 3 allow both flow cytometry fluorescence confocal microscopy studies cytotoxicity. With effectors, appears subsequent that inside all targets. Overexpression Bcl-2 minimal effects on lysis, NK- CTL-delivered activity, 3. Detection followed provides unique readout potentially lethal injury delivered lymphocytes.