Caspase-3–like activity is activated by Siglec-8 cross-linking. Cells were cultured for 24 hours under control or cross-linking conditions, as indicated, and analyzed for caspase-3–like activity in the presence and absence of the caspase-3 inhibitor Ac-DEVD-CHO (20 μM). Data are mean ± SEM from 3 experiments. *P ≤ .05 for comparison of 2E2 + 2° Ab versus medium control; †P ≤ .05 for comparison of 2E2 + 2° Ab versus 2E2 + 2° Ab + inhibitor.