DL1 does not affect pDC proliferation or apoptosis. (A) CD34⁺CD1a^- cells were labeled with CFSE and cocultured with OP9-DL1, OP9-Jag1, or control cell lines. CFSE content of BDCA2⁺CD123^hi pDCs was analyzed after 1 week of coculture (n = 3). (B) CD34⁺CD1a^- cells were cocultured with OP9-DL1, OP9-Jag1, or control cell lines and analyzed after 1 week of culture for the percentage of Ki-67⁺ pDCs. Percentages of Ki-67⁺CD123^hiBDCA2⁺ pDCs above background levels are indicated next to the histograms (n = 2) or (C) percentage apoptotic (annexin V⁺7-AAD^-) pDCs (n = 2). Experiments representative of at least 2 experiments are shown.