LCs support survival of resting and DC-activated NK cells. (A) CD56 and CD16 expression was quantified on gated CD3^- lymphocytes by flow cytometry. Percentages indicate CD16^-CD56^bright (LUQ), CD16⁺CD56^bright (RUQ), and CD16⁺CD56^dim (RLQ) cells. Note that most of the peripheral blood NK cells are CD56^dim but not CD56^- directly after isolation from PBMCs or after coculture with LCs. One of 4 independent experiments is shown. Percent surviving NK cells in the lower panel indicates the average sum of the percentages for CD16^-CD56^bright, CD16⁺CD56^bright, and CD16⁺CD56^dim cells in the 4 experiments and their standard deviation. (B) Proliferation of purified peripheral blood NK cells was assessed by ³H-thymidine incorporation after culture with (left panel) monocyte-derived dendritic cells (moDC; •) or with CD34⁺ HPC-derived Langerhans cells (LC; ○) or dermal-interstitial dendritic cells (DDC-IDC; ▾) or (right panel) with 1:1 mixtures of moDCs plus moDCs (moDC+moDC; •), LCs (moDC+LC; ○), or DDC-IDCs (moDC+DDC-IDC; ▾) for 6 days. Data points for the indicated NK-cell-dendritic cell ratio (X-axis; NK/DC from 3:1 to 1000:1) represent the average of duplicate microwell cultures and their standard deviation. The data are representative of 3 independent experiments.