CD56^dim NK-cell differentiation and education are uncoupled events. (A) Expression of CD57 on KIR⁻NKG2A^+/− (left), singleKIR⁺NKG2A⁻ educated or uneducated (middle) CD56^dim NK-cell subsets, and NKG2A⁻ subsets coexpressing 2 KIRs (right) (n = 28 left, 27 and 48 middle, 9 and 54 right; n.s., not significant; mean). (B) CFSE dilution in singleKIR⁺CD57^+/− educated and uneducated NK-cell subsets (left) and CD57^+/− subsets coexpressing 2 KIRs (right) after 5 days of IL-2 stimulation (n = 13 and 14 left, 20 and 45 right; ***P < .001; mean). (C) Representative example of an HLA C1/C1 homozygous donor showing CD107a expression of uneducated (KIR2DL1) and educated (KIR2DL3) after coculture with K562 cells for 6 hours. (D) Representative example of an HLA C1/C1 homozygous donor showing IFN-γ expression after 24 hours of stimulation with IL-12 + IL-15 of the indicated subsets. (E) Degranulation (CD107a expression) in KIR⁻NKG2A^+/−CD57^+/− (left) and singleKIR⁺NKG2A⁻CD57^+/− educated and uneducated CD56^dim NK-cell subsets after coculture with K562 cells for 6 hours (n = 26 left, 37 and 34 right; n.s., not significant; ** P < .01; mean). (F) Expression of IFN-γ in KIR⁻NKG2A^+/−CD57^+/− (left) and singleKIR⁺NKG2A⁻CD57^+/− educated and uneducated CD56^dim NK-cell subsets after 24 hours of stimulation with IL-12 + IL-15 (n = 10 left, 12 and 14 right; n.s., not significant; ** P < .01, *** P < .001; mean). (G) Expression of IFN-γ in KIR⁻NKG2A^+/−CD57^+/− (left) and singleKIR⁺NKG2A⁻CD57^+/− educated and uneducated CD56^dim NK-cell subsets after 18 hours of priming with IL-12 + IL-15 and 6 hours of coculture with K562 cells (n = 10 left, 15 right; **P < .01, ***P < .001; mean). (H) Relative contribution of CD57 and education to detected responses after stimulation with IL-2 for proliferation, K562 cells for degranulation, IL-12 + IL-15 for IFN-γ production, and IL-12 + 15 priming, followed by coculture with K562 cells for IFN-γ production (mean).