Recombinant interferon alpha 2 stimulation of target-binding by natural killer cells.

Even though the enhancement of the lyitc capacity and the kinetics of lysis of natural killer cells (NK) by interferon has been well documented, an increase of the target-effector cell binding percentage is still disputed. We, therefore, modified the Grimm-Bonavida single-cell assay so that 400 to 600 cells per individual determination could be reliably evaluated. Using this assay, which makes possible separate determination of effector-target cell binding and target lysis, we demonstrated that, in addition to lytic capacity, target-effector cell binding is also increased by preincubating NK with 100 to 1,000 IU interferon alpha 2 per 10(6) cells. Our data indicate that interferon alpha 2 induces pre-NK cells to bind target cells and that it activates these pre-NK cells to kill the targets.