Triggered degranulation and cytokine release. Purified IL-2–activated NK cells were incubated in microtiter wells coated with no Ab, anti-CD16 MoAb, anti-CD38 F(ab′)₂, anti-CD56 MoAb, or anti–MHC-1 MoAb for 3 (esterase release) or 20 (cytokine release) hours. Supernatants were removed and tested for BLT-esterase (upper panel), TNF- (middle panel), or IFN-γ (lower panel). Cells from different donors were used for measuring esterase and cytokine release. *P < .05. **P < .01 as compared with the no antibody control.