Fig. 1. Gating techniques used to identify NK subsets in whole blood samples. Each dot indicates a single cell analyzed by flow cytometry. As each cell is forced to pass through the laser beam, the cell is interrogated by the laser and scatters the light. Several detectors measure the light scattered from cells as either forward scatter (FS) or side scatter (SS); these measures are correlated with the size and granularity, respectively. The y-axis in panel (A) represents the amount of lights detected as SS, which is expressed using a linear scale. The intensity of the fluorescence obtained from cells stained with fluorescent antibodies is expressed using a logarithmic scale on the x- or y-axis of panel (A)–(C). After the lymphocytes were gated (A), NK cell subsets (CD3⁻/CD56⁺) were sequentially gated on the basis of the surface expression of CD3 (T-lymphocyte) and CD19 (B-lymphocyte)/CD14 (monocyte) (B). Finally, CD3⁻/CD56⁺ cells were gated into 2 main subsets and 5 subsets depending on the expression of CD56 and CD16 (C). The numbers in panel (C) represent the following subsets: 1) CD56^bright/CD16⁻, 2) CD56^bright/CD16⁺, 3) CD56^dim/CD16⁻, 4) CD56^dim/CD16⁺, and 5) CD56⁻/CD16⁺.