Activated and expanded CD8⁺ T cells function through NKG2D. (A) Cytolysis against the plasmacytoma cell line U266. Effectors were combined with targets (E/T = 10:1) either alone (▪) or in the presence of isotype control antibodies (▦) or NKG2D antibodies (□). Antibodies were used at a final concentration of 20 μg/mL and results are representative of 3 or more experiments. Error bars indicate standard deviations. (B) FACS histograms demonstrating the presence or absence of NKG2D ligands on the U266 cell line. Dotted lines represent isotype control and solid lines, the antibody directed against the stated NKG2D counterligand. (C) ⁵¹Cr release assay was performed as in panel A, except in the presence of antibodies directed against NKG2D, MICA, ULPB3, or isotype control antibodies. Data are expressed as a percent reduction in cytotoxicity.