Surface phenotype of IL-22⁺ stage 3 iNK cells. Total CD3⁻CD19⁻CD34⁻ resting tonsillar mononuclear cells were stained for surface expression of lineage markers, CD117, CD94, followed by intracellular expression of IL-22, and events were gated on total Lin⁻CD117⁺CD94⁻IL-22⁺ stage 3 iNK cells. (A) Representative histograms show expression for each indicated surface marker (shaded) in a donor, compared with isotype control (clear). (B) Graphic summary of the mean proportion of IL-22⁺ stage 3 iNK cells expressing various surface markers from all (n = 4) donors is summarized. Error bars represent standard error of the mean.