CD56^dim and CD56^bright KIR⁻ cells are precursors to receptor-expressing NK cells. CD56^dim and CD56^bright NK cells were sorted according to NKG2A and KIR expression, analyzed for NKR expression, cultured for 14 days on EL08–1D2 cells with IL-15, and then reanalyzed for NKR expression. (A) Shown is a representative analysis of the 4 subpopulations of CD56^dim cells. The postsort analysis of each starting population (top row) is compared with similar analysis after culture to induce further maturation (bottom row). (B) Shown is an analysis of the CD56^bright population in which essentially all cells were NKG2A⁺ (not shown). The postsort analysis (top) is compared with that after culture with EL08–1D2 cells and IL-15 (bottom).