(D) YTS KIR2DL1 cells were treated with SHP-1 and Cbls siRNAs-loaded NPs or N.S siRNA-loaded NPs. After 48 hours, cells were incubated with either 721.221 Cw4 or Cw7 target cells, the supernatant was then collected, and granzyme B levels were evaluated using ELISA sandwich assay. The levels of granzyme B were quantified based on a standard curve. Data are means ± SEM of five independent experiments. (n=5). P values were calculated by One way ANOVA following Tukey's post hoc analysis, and are indicated by asterisks. **P < 0.01. 