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. 2021 Sep 24;18(4):1021–1039. doi: 10.20892/j.issn.2095-3941.2020.0791

Figure 1.

Figure 1

NK cells with trained immunity exhibit enhanced effector responses. (A) Overview of the experimental design. PBMCs were preactivated with IL-12 (10 ng/mL), IL-15 (1 ng/mL), and IL-18 (50 ng/mL), or control (1 ng/mL of IL-15 alone) for 16 h, washed, and then cultured under low concentrations of IL-15 (1 ng/mL) for differentiation. Flow cytometry analysis was performed at the indicated time points after preactivation. (B) Left panel: flow cytometry plot showing the gating strategy for CD3−CD56+ NK cells; right panel: histogram showing enhanced IFN-γ production by cytokine-trained NK cells restimulated with IL-12/18 on day 7. (C) Increased killing of K562 leukemia target cells by cytokine-trained NK cells on day 7. (D) Upper panel: representative flow cytometry data showing increased basal levels of granzyme B (GzmB) and expression of TNF-α, IFN-γ and Ki67 in cytokine-trained NK cells restimulated on day 7 by PMA+ionomycin; lower panel: summary data showing the median fluorescence intensity (MFI) of GzmB, TNF-α, IFN-γ, and Ki67. For all experiments, n = 7, *P < 0.05, **P < 0.01, and ***P < 0.001 (error bars, mean ± SEM). Data are representative of at least 3 independent experiments.