C5 does not activate caspase 8, 2, or 9.

(A) HL60 cells were treated with 150 μg/mL C5 or 100 μg/mL C2 for 12 hours, and lysates were analyzed for caspase 8, 2, or 9 activation by fluorometric assays designed to detect cleavage of the AFC-conjugated specific substrate (IETD-AFC for caspase 8, VDVAD-AFC for caspase 2, and LEHD-AFC for caspase 9), as described in “Materials and methods.” Caspase activity is expressed as fold increase (x increase) over the activity obtained in untreated cells, shown here as 1 × . (B) Lysates obtained from C5- and C2-treated HL60 cells were also analyzed by SDS-PAGE and Western blotting for cleavage of PARP (85-kd fragment) using a monoclonal anti-PARP antibody.