Effect of PGE2 matured DC on NK-cell function. (A) IFN-γ/FMKp–matured DCs with or without 5 μg/mL PGE2 were cultured for 24 hours in the presence or absence of freshly isolated NK cells. IFN-γ/FMKp matured DCs were coated with SEB and cocultured with freshly isolated CD45RA⁺/RO⁻CD4⁺ T_H cells; every other day, stimulation medium was exchanged with supernatant from IFN-γ/FMKp–matured DCs (with or without 5 μg/mL PGE2) cultured with or without NK cells. (B) Percentage of naive CD4⁺ T cells accumulating IFN-γ after 10 days of coculture and stimulation with PMA/ionomycin for 4 hours as analyzed by flow cytometry, gated on CD4⁺CD3⁺ T cells. Representative data of 1 of 3 independent experiments are shown. (C) CD45RA⁺/RO⁻CD4⁺ T_H cells accumulating intracellular IFN-γ of 5 different donors. Results presented are the mean of combined data of 5 different donors + SEM. (D) Freshly isolated human NK cells and undiluted, filtered supernatants of IFN-γ/FMKp DCs matured in the presence of different concentrations of PGE2 were used for induction of NK-cell cytotoxicity. NK-cell cytotoxicity toward Raji cells was assessed by a flow cytometry–based kill assay. Data represent means ± SEM of triplicate wells. Data shown are representative of 3 independent experiments. (E) Cytotoxicity toward Raji without and after preincubation and early incubation of NK cells with PGE2 and activation in DC supernatant. Data represent means + SEM of triplicate wells of effector:target (E:T) ratio of 10:1. Data are representative of 3 independent experiments. *P < .05.