CCR7 expression on alloreactive and “licensed” NK cells after exposure to allogeneic DCs or HLA-class I–negative Epstein-Barr virus cell line. (A-C) Alloreactive and nonalloreactive NK-cell clones were assessed for their ability to kill mDCs in a ⁵¹Cr-release assay at an E/T ratio of 5:1. The cytolytic activity of NK-cell clones against mDCs was assessed either in the absence or in the presence of anti–HLA-class I mAb (A). The SD did not exceed 4% in the ⁵¹Cr-release assays. The same NK clones were also analyzed for CCR7 acquisition after 1-hour coculture with mDCs in the absence or in the presence of anti–HLA-class I mAb (B). In panel B, the values reported in the top right corners indicate the percentage of CD56⁺, CCR7⁺ NK cells. Data are representative of 7 independent experiments performed using different NK clones. (C) Peripheral blood NK cells from a C1⁺/C1⁺ donor were cultured with 221 cells and subsequently stained with anti-CCR7, anti-KIR, and anti-NKG2A mAb. (Top panels) unlicensed NK cells (top left quadrant) lacking KIR2DL2/3, KIR3DL1, and NKG2A were compared for CCR7 acquisition with licensed NK cells (top right quadrant). (Bottom panels) Cells expressing KIR2DL2/3 alone (top left quadrant) or in combination with either KIR3DL1 or NKG2A (top right quadrant) were evaluated for CCR7 acquisition. Similar results were obtained in 2 additional experiments.