Figure 7.

Engulfed apoptotic cells inhibit proinflammatory cytokine release. J774A.1 macrophages were incubated at 37°C without or with LPS at the indicated concentrations for 2 h before the addition of late apoptotic (□) or necrotic (○) DO11.10 targets (prepared as in Figure 1; target to macrophage ratio of 20:1) or without added targets (▴). Culture supernatants were collected 4 h after target addition, and levels of secreted TNF-α and IL-6 were quantified. Under these conditions, target cells themselves produced no detectable levels of cytokines (<10 pg/ml TNF-α and < 15 pg/ml IL-6).