Effect of PGE2 matured DCs on IL-22 production by NK cells residing in the tonsil. Monocyte-derived DCs were matured with IFN-γ/FMKp in the presence or absence of 50 ng/mL PGE2. After 6-hour maturation, DCs were washed to remove the stimulation medium and matured for an additional 18 hours in AIM V medium only. (A) Percentage of NKp44⁺ NK cells isolated from tonsils, accumulating IL-22 after 16 hours of coculture as analyzed by flow cytometry, gated on CD56⁺CD3⁻ cells. Representative data of 1 of 6 independent experiments are shown. (B) NKp44⁺ NK cells accumulating intracellular IL-22 of 7 different donors. In 6 of 7 donors, there is an increase in percentage of IL-22–positive NK cells. Wilcoxon signed rank test significance, *P < .05.