Figure 5.

The cytotoxicity of dNK cells was regulated by CD39/CD73 enzyme activity. (A–C) Freshly isolated dNK cells from healthy donors were incubated in the absence or presence of the CD39 inhibitor ARL67156 for 24 hours, and then stained for the surface expression of the cytotoxicity markers NKG2D (A), NKp30 (B) and NKp44 (C). All experiments were performed in triplicate (mean ± SEM, *P < 0.05, **P < 0.01 by two-tailed t tests). (D, E) Effects of CD39 on the degranulation of activated dNK cells from healthy donors. To quantify degranulation, the surface expression of CD107a was measured after activation of isolated dNK cells were incubated with or without (W/O) the NK-susceptible target cell line (K562 cells) in the absence or presence of the CD39 inhibitor ARL67156 for 24 hours (mean ± SEM, **P < 0.01 compared with the untreated group, one-way ANOVA and post hoc tests). (F, G) dNK cells isolated from healthy donors co-cultured with HTR-8/SVneo cells (dNK : HTR-8/SVneo cells = 2:1) in the absence or presence of the CD39 inhibitor ARL67156 and/or CD73 inhibitor APCP for 24 hours. The percentage of dNK cells expressing CD107a was used as the indicator of degranulation (mean ± SEM, *P < 0.05, **P < 0.01, one-way ANOVA and post hoc tests).