Eph expression in different subsets of CD34⁺-derived DCs generated in vitro and of skin Langerhans cells isolated ex vivo. Cord blood CD34⁺ progenitors were cultured in the presence of GM-CSF, SCF, TNF-α, and 2.5% AB⁺ human serum. At day 6, CD1a⁺ and CD14⁺ precursors were sorted by flow cytometry and recultured with GM-CSF and TNF-α for 6 additional days. The presence of Eph transcripts in the 2 purified subsets was compared to total CD34⁺-derived DCs (DC TOT, corresponding to unsorted cells). cDNA was prepared from basal cells and from Langerhans cells, freshly isolated from normal skin. RT-PCR was carried out under standard conditions using 50 ng cDNA for 40 cycles. All cDNA samples were normalized according to the results of β-actin PCR amplification of 21, 28, and 35 cycles (only the amplification of 28 cycles is shown). Results are representative of 3 independent RT-PCR samples.