Differential expression levels of H60 influence the Ly49C/I receptor-mediated inhibition. (A) The effect of inhibitory Ly49 receptors on cytotoxicity was tested using Ly49C/I-specific SW5E6 or (B) Ly49I-specific YLI-90 mAbs at titrated concentrations (ST63 •, ST61 ▴, and EL4 ▪; respective open symbols denote no antibody) and (C-D) with different E/T ratios using constant amounts of mAbs (2 μg per well) (histograms). Note different Y-axis scales for ST61 and ST63 data. Results presented as the mean percent cytotoxicity ± SD and are representative of 3 independent experiments.