Smac mimetics stimulate cytokine production in macrophages prior to initiation of cell death. (A) WT or Tnf^−/− BMDMs were either left untreated or stimulated in culture for 24 hours with the Smac mimetic Comp. A (500 nM). The concentrations of the cytokines indicated were measured by multiplex bead assays. N = 4 experiments with BMDMs from individual WT mice; N = 2 experiments with BMDMs of individual Tnf^−/− mice. (B) LDH release was measured in supernatants of WT and Tnf^−/− BMDMs after treatment with 500 nM Comp. A over 0-8 hours. N > 6 experiments with BMDMs from individual WT mice. (C) WT BMDMs were stimulated in culture for the times indicated with 500 nM Comp. A, and TNF was measured in cell lysates and supernatants. N > 3 experiments with BMDMs from individual WT mice. (D) WT BMDMs were stimulated in culture for the times indicated with 500 nM Comp. A. Culture supernatants were assayed for various cytokines by multiplex bead assay. N = 3 experiments with BMDMs from individual WT mice. Mean ± SEM are shown. **P < .01; *P < .05.