CD38 is involved in mMDDC protection from apoptosis induced after withdrawal of growth factors. (A) iMDDCs were either untreated (none) or treated with LPS alone, sCD38 alone, or LPS plus sCD38 for 24 hours. Shown is one representative experiment of 9 performed. (B) iMDDCs were either untreated (none) or treated with LPS alone, anti-CD31 mAb (Moon-1) alone, or LPS plus anti-CD31 mAb for 24 hours. One representative experiment of 4 performed is shown. (C-D) Cumulative apoptosis values (means ± SE of 4 to 9 independent experiments, according to the experimental conditions) are presented as percentage of apoptosis compared with untreated cells (100% spontaneous apoptosis; none). The percentage of spontaneous apoptosis (mean ± SE [range] of 9 donors) of untreated MDDCs was 27.5% ± 3.5% (8.7%-63.2%). Agonistic anti-CD38 mAb (IB4) was added as indicated. Statistically significant differences are indicated. (E) iMDDCs were either untreated (none) or treated with LPS alone or LPS plus sCD38 for 24 hours. Agonistic anti-CD38 mAb (IB4) was added as indicated. Cells were intracellularly stained for Bcl-2 expression. One representative experiment of 4 performed is shown. (F) Cumulative Bcl-2/Bax ratio values calculated after 24 hours of culture in the same conditions as in panel C. Results are expressed as mean ± SE of 4 to 9 independent experiments, according to the experimental conditions. (G) iMDDCs were either untreated (none) or treated with LPS alone or LPS plus sCD38 for 48 hours. iMDDCs were also treated with FCCP as control. Cells were stained with DePsipher. Percentages of gated cells displaying decreased ΔΨ_m are indicated. One representative experiment of 3 performed is shown. (A-B, E) Numbers in graphs are percentages of positive cells.