(E) Killing assay. YTS KIR2DL1 cells were mock-transfected or transfected with N.S siRNA or SHP-1 and Cbls siRNA. After 48 hours, cells were incubated with [35S] Met-loaded 721.221 Cw4 or Cw7 target cells. After 5 hours of co-culture, the supernatant was collected, and the radioactive signal was measured. Data are means ± SEM of three independent experiments. P values were calculated by One-way ANOVA following Tukey's post hoc analysis and are indicated by asterisks *P < 0.05, **P < 0.01 . 