Expression levels of H60 differentially activate purified Ly49C⁺/I⁺ compared with Ly49C^-/I^- NK subsets. The effect of Ly49C/I receptors on NK cell-mediated cytotoxicity was tested as described in the legend to Figure 1B using sorted subsets of Ly49C⁺/I⁺ and Ly49C^-/I^- NK cells and are representative of 3 independent experiments. Data presented are the mean values of percent cytotoxicity against indicated target cells with Ly49C⁺/I⁺ (□) or Ly49C^-/I^- (▪).