Efficient naive T-cell proliferation is induced by CD1a-or CD14-derived DCs. Cord blood CD34⁺ HPCs were cultured in the presence of GM-CSF plus TNFα. After 5 to 6 days cells were collected, processed for double staining using anti-CD14–PE and anti-CD1a–FITC, and FACS-sorted into CD14⁻CD1a⁺ and CD14⁺CD1a⁻. Sorted cells were seeded in the presence of GM-CSF plus TNFα (1 to 2 × 10⁵ cells/mL) for 6 to 7 additional days, with last medium changes being performed at day 10. (A and B) At the indicated time points, independent aliquots of cells were harvested and used, after irradiation (30 Gy), as stimulator cells for CD45RA⁺ CD4⁺ naive cord blood T cells (2 × 10⁴ cells/well). For day 0, uncultured CD34⁺ HPCs were used as stimulator cells. T cells from the same batches were used each time after thawing. Proliferation of allogeneic T cells induced by 10³ stimulator cells is shown (A). Proliferation of syngeneic T cells in absence or presence of 1 ng/mL SEA induced by 10² stimulator cells is shown in (B). (C and D) Cells were recovered at day 12 and used after irradiation (30 Gy) as stimulator cells for cord blood CD45RA⁺ CD4⁺ T cells (2 × 10⁴ cells/well; C) or cord blood CD8⁺ T cells (2 × 10⁴ cells/well; D). Proliferation was shown by ³H-TdR uptake after 5 days of culture. Results are expressed as mean cpm ± SD of triplicate cultures. Results of each panel are representative of three experiments or more.