Cd94 Ligation Induces Apoptosis In A Subset Of Il-2-Stimulated Nk Cells

CD94 (Kp43) is a member of the human C-type lectin superfamily encoding type II membrane glycoproteins expressed on NK cells and a subset of T cells, Ligation of CD94 has been shown to either potentiate or inhibit NK cell proliferation and cytolytic effector function, Here we show that CD94 ligation triggers apoptosis in IL-2-primed NK cells, Evidence for CD94-induced apoptosis includes: 1) chromatin condensation as measured by increased fluorescence of Hoechst dye, 2) induction of DNA fragmentation, and 3) characteristic morphology by transmission electron microscopy. IL-2 priming (at least 12 h) is required for activation-induced NK cell death triggered by CD94, Activation-induced NK cell death triggered by CD94 ligation is extremely rapid (DNA fragmentation is first observed at 120 min), Unlike activation-induced T cell death, it is not inhibited by neutralizing Abs reactive with TNF-alpha or Fas ligand, Our results suggest that CD94 may play a role in the elimination of activated NK cells during the transition from the innate to the Ag-specific immune response.