Elastase, or cathepsin G, inhibits ingestion of apoptotic cells. (a) HMDMs were cocultured with apoptotic Jurkat cells in the presence of media or increasing concentrations of elastase, cathepsin G, or proteinase 3. The mean phagocytic index as percentage of control ± SEM is shown for three to six replicates per group. Control mean phagocytic index: 44.1 ± 8.5. *Significantly different from media (P < 0.05). (b) Human AMs were cocultured with apoptotic human PMNs following pretreatment with media (Control), 1 μM PMN elastase (NE) with or without a specific elastase inhibitor (NEI, 100 μM), or 1 μM cathepsin G (Cat G) with or without a specific CGI (10 μM). Coculture was done in the presence of DMP777 (20 μM) to prevent carryover of elastase activity. The mean phagocytic index as percentage of control ± SEM is shown for three or four replicates per group. Control mean phagocytic index: 8.4 ± 1.9. *Significantly different from control (P < 0.05).