Effects of specific GrB and PFN inhibitors
| Effector cells and treatment . | Target cells (% of cytotoxicity) . | |
|---|---|---|
| K562 . | Jurkat . | |
| KG1a | 2.8 (±0.4) | 2 (±0.5) |
| KG1a + IR | 22 (±4.2) | 28.5 (±2.4) |
| KG1a + IR + DCIC | 0.8 (±0.2)* | 2.7 (±1.4)* |
| KG1a + IR + MgCl2/EGTA | 0.6 (±0.3)* | 1 (±2.4)* |
| KG1a + IR + anti-TNF-α (blocking) | 19.8 (±1.2) | 25.5 (±1.8) |
| KG1a + IR + anti-CD95 (blocking) | ND | 22 (±3.4) |
| PBL/IL-2 | 50 (±5.5) | 55 (±4.3) |
| PBL/IL-2 + DCIC | 11.7 (±2.1)* | 8 (±1.4)* |
| PBL/IL-2 + MgCl2/EGTA | 3 (±1.3)* | 4.3 (±2.7)* |
| Effector cells and treatment . | Target cells (% of cytotoxicity) . | |
|---|---|---|
| K562 . | Jurkat . | |
| KG1a | 2.8 (±0.4) | 2 (±0.5) |
| KG1a + IR | 22 (±4.2) | 28.5 (±2.4) |
| KG1a + IR + DCIC | 0.8 (±0.2)* | 2.7 (±1.4)* |
| KG1a + IR + MgCl2/EGTA | 0.6 (±0.3)* | 1 (±2.4)* |
| KG1a + IR + anti-TNF-α (blocking) | 19.8 (±1.2) | 25.5 (±1.8) |
| KG1a + IR + anti-CD95 (blocking) | ND | 22 (±3.4) |
| PBL/IL-2 | 50 (±5.5) | 55 (±4.3) |
| PBL/IL-2 + DCIC | 11.7 (±2.1)* | 8 (±1.4)* |
| PBL/IL-2 + MgCl2/EGTA | 3 (±1.3)* | 4.3 (±2.7)* |
KG1a cells were treated with either DCIC (20 μmol/L; GrB inhibitor) or MgCl2/EGTA (1.5 mmol/L; PFN inhibitor) after irradiation (4 Gy) and incubation for 72 hours and then were allowed to react with target cells (K562 or Jurkat) for 4 hours. Effector and target cells were co-incubated in the presence of anti-TNF-α or anti-CD95 blocking monoclonal antibodies for 4 hours. Cytotoxicity was measured by a 4-hour nonradioactive lactate dehydrogenase-release assay. Results are the mean ± standard deviation of three independent experiments performed in triplicate.
GrB indicates granzyme B; PFN, perforin; IR, ionizing radiation; DCIC, 3,4-dichloroisocoumarin; TNF-α, tumor necrosis factor α.
P = .02.