Interleukin 2 mediates p72syk activation in peripheral blood lymphocytes

The ability of interleukin 2 (IL-2) to stimulate p72syk activity in intact porcine peripheral blood lymphocytes was examined. We demonstrated that IL-2 activated p72syk in a time- and dose-dependent manner, for which its peak time and maximum responsive dose were 5 min and 100 U/ml, respectively. This activation was observed only in cytosolic fractions and not in membrane ones. However, IL-2 failed to induced calcium mobilization. Moreover, IL-2-inducible p72synk activation was not affected when extra- intracellular calcium was depleted. These data suggest that the IL-2 signaling pathway through p72syk in peripheral blood lymphocytes is different, at least in part, from other agonists, such as concanavalin A in polymorphonuclear neutrophils which can trigger both the activation of p72syk and intracellular calcium mobilization.