Early caspaselike activation in DCs exposed to LPS. (A) DCs were loaded with FITC-VAD and then left untreated or exposed for 30 minutes to LPS (100 ng/mL), with or without 1 hour pretreatment with zVAD (40 μM) or cell-permeable YVAD (4 μM). FITC-VAD–loaded DCs were also exposed to UVB with or without pretreatment with zVAD. Cell fluorescence intensity was analyzed by flow cytometry. (B) The percentage of FITC-positive cells at different time points is shown for each of the above mentioned conditions. Means ± 1 SD from 3 independent experiments are shown. Each experiment was performed in duplicate.