FIG 4.

Caspase-1-independent macrophage lysis occurs at later time points and/or higher organism burdens. (A) Bone marrow-derived macrophages (BMDM) from C57BL/6 (WT) or caspase-1-deficient (casp1^−/−) mice were prestimulated with LPS for 2 h and then exposed to C. albicans at an MOI of 2:1 for 5 h. LDH was measured from the supernatant and is expressed as the percentage of maximum release as described in the Fig. 1 legend. Each experiment was performed at least three times, and results of representative experiments are shown. Bar heights represent the mean results of technical replicates (n = 3), and error bars indicate standard deviations. (B) The percentage of caspase-1-dependent cell lysis was calculated as 100 × [100 − (result for casp1^−/− BMDM)/(result for WT BMDM)]. Data points represent the means and error bars indicate the propagated errors as calculated from the original standard deviations. Data were analyzed by Student's t test: **, P ≤ 0.001 compared to control. (C) Parallel samples were cocultured in 8-well chamber slides. At the end of the exposure, slides were rinsed once with PBS and once with distilled water, allowed to dry, and then Gram stained. Photomicrographs of representative fields are presented. The experiment was performed twice; results were similar for the two experiments.