Natural killer cells do not lyse resting or mitogen-stimulated B cells.

It has recently been reported that isolated resting natural killer cells lyse autologous resting and mitogen-stimulated B cells. In this report, we have been unable to corroborate these observations and provide indirect evidence that lytic susceptibility is attributable to exposure of the target cells to xenogeneic antigens present in fetal calf serum (FCS). Moreover, we show that interleukin-2-activated killer cells potently lyse normal peripheral blood mononuclear cells which are exposed to FCS.