The activity of natural cytotoxic cells is augmented by interleukin 2 and interleukin 3

Murine natural killer (NK) and natural cytotoxic (NC) cells showed different patterns of augmentation of lytic activity after preincubation for 24 h with either poly-IC, interleukin 2 (IL-2), or interleukin 3 (IL-3): (a) Poly-IC augmented only NK cells, with no effect on NC activity, as we have previously observed (4); (b) IL-2 augmented both NK and NC activity; and (c) IL-3 augmented only NC lysis, without affecting NK activity. In addition, both precursor and the augmented effector cells showed differences in expression of the Qa- 5 surface marker: NK precursors and effectors are Qa 5+, whereas NC precursors and effector cells are Qa-5-.