PGE₂ positively regulates Flt3L-dependent DC development from hematopoietic progenitor cells. (A) Total cDC (CD11c⁺ CD11b⁺ B220⁻) and pDC (CD11c⁺ CD11b⁻ B220⁺) generation from Lin^neg BM cells in Flt3L cultures in presence of indomethacin or indomethacin plus dmPGE₂ (mean ± SEM; n = 3 mice/group in each of 2 experiments). (B) Detection of PGE₂ at indicated time points during Flt3L-mediated DC differentiation in culture from panel A. (C) Total DC generation from CDPs (10³ cells/well) that underwent FACS and cultured for 9 days in Flt3L-supplemented media in the presence/absence of indomethacin (mean ± SEM; n = 5 mice; 2 experiments). (D) Total DC generation from Lin^neg BM cells (2 × 10⁵ cells/well) cultured for 9 days with Flt3L and SC560 (COX1 inhibitor) or NS398 (COX2 inhibitor) or different dose of PGE₂ (0.1nM-100nM; mean ± SEM; n = 6 mice; 2 experiments). (E) Effect of indomethacin treatment on CD34⁺ CD11a⁺ CD14⁻ DC precursor and CD11c⁺ CD14⁻ myeloid DC generation from purified UCB CD34⁺ cells (5 × 10⁵ cells/well; mean ± SEM; n = 3 cord blood samples). (F) Total DC generation from mouse Lin^neg BM cells cultured with GM-CSF with or without indomethacin (mean ± SEM; n = 5 mice). *P < .05. V indicates vehicle; and Indo, indomethacin.