Assessment of endothelin axis influence on DC death. (A) Cell death assessment with Annexin V assay. Mature DCs (DC + SA) were treated either with ABT-627, ET_A receptor antagonist, or A-192621, ET_B receptor antagonist, and apoptosis was induced by dexamethasone (Dex, 10^-6 M) treatment for 48 hours. Untreated mature DCs served as a control. After 48 hours of treatment, DCs were collected, stained with Annexin V, and flow cytometry was performed for annexin-positive (early and late apoptotic) cells. Representative histograms from 1 of 3 experiments with similar results are shown. Isotype control (black lines) was anti-immunoglobulin G conjugated to fluorescein isothiocyanate. Gray lines indicate cells stained with annexin V. Numbers on horizontal bars indicate the percentage of annexin-positive cells. (B) DC death assessment with ELISA assay. Mature DCs (DC + SA) were treated either with ABT-627, ET_A receptor antagonist, or A-192621, ET_B receptor antagonist, and apoptosis was induced by dexamethasone (Dex, 10^-6 M) treatment for 48 hours. Untreated mature DCs provided control. After 48 hours of treatment, DCs were collected and the amount of cell death was determined using cell death ELISA kit (Roche Diagnostics) by assessing the amount of histone-associated DNA fragments (mononucleosomes and oligonucleosomes) in the cell lysates by a spectrophotometric reading at 405 nm wavelength. Combined data of 3 independent experiments are presented. ^*Statistically significant difference (P < .05) compared with mature DCs treated with dexamethasone only.