CD48 knockout renders ATLL cells resistant to direct cytotoxicity of primary NK cells isolated from healthy donors. (A-B) Normalized live-cell numbers of sgRNA-transduced ATLL cells under the cocultivation with primary NK cells isolated from (A) healthy donor #1 and from (B) healthy donors #2, #3, and #4. Data were obtained as shown in Figure 2B. (C) Expression of CD107a or IFNγ in primary NK cells detected by flow cytometry. NK cells from healthy donor #1 were cocultivated without ST1 or with sgCD48- or sgAAVS1-transduced ST1 for 6 hours. (D) The mean percentages of CD107a or IFNγ-positive NK cells shown in (C) were demonstrated by the bar graphs. Error bars represent the SEM of replicates. ∗P < .05, ∗∗P < .01, and ∗∗∗P < .001, Welch 2-sample t test. All experiments were repeated ≥2 times except for (B).