NK lytic-associated molecule: A novel gene selectively expressed in cells with cytolytic function

NK cells are most effective in killing a broad spectrum of primary tumor ce lls after stimulation with cytokines. We have cloned a novel gene, designat ed NKLAM (for NK lytic-associated molecule), whose expression is associated with this cytokine-enhanced process. NKLAM expression is up-regulated in N K cells by IL-2 and IFN-beta, NKLAM is also selectively expressed by activa ted macrophages and CTL. Treatment of NK cells and CTL with NKLAM antisense oligonucleotides specifically decreases their cytolytic activity, while ha ving no effect on cell growth. The NKLAM gene encodes a 62-kDa ring finger- containing protein that localizes to the cytoplasmic granules in NK cells, Further study of this gene may add to our understanding of cytotoxic proces ses common to NK cells, CTL, and activated macrophages.