(A) YTS KIR2DL1 and primary NK cells were incubated with NPs loaded with Cbl-b, c-Cbl and SHP-1 siRNA, or NPs loaded with 1500 pmol N.S siRNA. Following 48 hours of incubation, cells were lysed, and the membrane was blotted with anti-Cbl-b, anti-c-Cbl or anti-SHP-1 antibodies. GAPDH served as loading control. Densitometric analysis of the bands was performed using ImageJ and normalized to the GAPDH densitometry values. Analysis by ImageJ densitometry is summarized in the graph below. Data are means ± SEM of four independent experiments. (n=4). P values were calculated by One-sample t-tests and are indicated by asterisks. *P < 0.05, **P < 0.01. 