Compounds that enhance B. anthracis cytotoxicity. BMA, 8-HG, NBA, and IH were added to macrophages to a 100 μM final concentration. B. anthracis spores were then added to each sample. Macrophage necrosis, based on increased PI fluorescence intensity, was monitored at 5 h postinfection. Macrophage killing enhancement was calculated by normalizing the PI fluorescence intensity determined for each compound treatment by the PI fluorescence intensity for untreated macrophages. Error bars represent standard deviations of six independent measurements. *, P < 0.05; **, P < 0.01; ***, P < 0.001 (all for comparisons to untreated samples).