MePDN differently affects the IL-2– or IL-15–induced Tyr phosphorylation of STAT1, 3, and 5 and JAK3 molecules. Purified NK cells were cultured overnight with IL-2 (100 U/mL) or IL-15 (20 ng/mL) in the presence or absence (control = CTR) of different MePDN concentrations from 1 to 0.01 μg/mL (MePDN 1, MePDN 0.5, MePDN 0.1, MePDN 0.01). Total-cell lysates were analyzed by WB using antihuman antibodies against p-JAK3, p-STAT5, p-STAT1, and p-STAT3. Each membrane was probed again with antibodies recognizing the native proteins in order to assess comparable amounts of proteins, with the exception of JAK3. The α-tubulin derived from STAT3 membrane is shown as representative control. For p-JAK3 membranes, only the expression of α-tubulin was analyzed to assess comparable amounts of protein. These data are representative of 7 different experiments.