Specificity of 1-7F9 antibody. (A) Characterization of 1-7F9 specificity for KIR2D subtypes. Transduced BWZ cells expressing individual KIR2DL or KIR2DS receptors were incubated for 30 minutes with anti-KIR antibodies (1 μg/mL), as indicated. The 1-7F9 was detected with PE anti–human IgG4, and EB6, GL183, and FES172 were revealed with PE goat anti–mouse IgG. Results shown are representative of 4 separate experiments. (B) Human whole blood from a healthy volunteer was stained with PE-conjugated 1-7F9; dot plots represent 1-7F9 binding to the indicated leukocyte subsets based on forward/side light scatter. (C) Human whole blood from a healthy volunteer was stained with PE-conjugated 1-7F9 and a combination of mAbs defining various leukocyte subsets, and analyzed by flow cytometry. Experiments in panels B and C have been performed on 11 healthy donors. Mean percentage and SD of 1-7F9–positive cells among the NK- and T-cell populations were 48.1% ± 14.9 and 2.4% ± 2.1, respectively. (D) Titration of 1-7F9 mAb on KIR2D-transduced BWZ cell lines. Cells were incubated for 30 minutes with 1/3 serial dilutions of 1-7F9, which were then revealed with PE anti–human IgG4 and analyzed by flow cytometry. Each dilution point was performed in duplicate. , ■, ▲, and ● represent cell lines expressing KIR2DL1, KIR2DS1, KIR2DL3, and KIR2DS2, respectively. Mean and SD of data collected in 2 independent experiments are shown.