Dissection of human CD56⁺CD3⁻ NK-cell subsets by CD94 surface expression. (A) Mononuclear cells freshly isolated from peripheral blood were stained with anti-CD3, anti-CD56, and anti-CD94 fluorescently labeled mAb. CD56⁺CD3⁻ NK cells were then gated for quantification of CD94 surface density. The dot plot shown is for a representative donor, and the numbers in the plot are averaged from 14 healthy donors and represent the percentage of total NK cells ± SD belonging to each subset of CD94^highCD56^bright, CD94^highCD56^dim and CD94^lowCD56^dim. (B) Comparison of CD94-PE antibody staining (gray) and its isotype control IgG1-PE staining (black) of NK cells gated on CD56⁺CD3⁻.