IFN-λ–treated DCs keep their antigen uptake abilities and do not release IL-12p70 in vitro. (A) iDCs were left untreated or were treated with IFN-β, IFN-λ, or LPS for 24 hours. Cells were incubated for 30 minutes with 1 mg/mL FITC-dextran particles at 37°C or at 4°C. DC uptake ability was accessed by flow cytometry. Dextran uptake at 37°C by IFNs or LPS-treated DCs (black line) were compared with iDCs (filled gray areas) and 4°C control conditions (filled black areas). Experiments were performed in duplicate and are representative of mean results obtained with cells from 5 blood donors. (B). The release of IL-12p70 by DCs in culture supernatant was determined after 48 hours of maturation by IFNs, LPS, or medium (▪) or after 8 days of MLR culture at a 1:10 DC/T ratio (□). Results are the mean ± SEM of 3 to 4 independent experiments performed on different blood donors.