IFN-λ influences the DCs phenotype and functional capacity.

<p>Monocyte-derived DCs from healthy individuals were generated without (control) or with a combination of IL-29 and IL-28A (control+IFN-λ), or from patients with chronic HCV (HCV+IFN-λ) or recovered HCV infection (SVR+IFN-λ) for 7 days, after which they were included in a mixed lymphocyte reaction (MLR) with allogeneic CD4⁺ T cells for 4 days. Incorporation of ³H-Td during the last 16 hours of MLR, read as counts per minute (cpm), was considered indicative of the stimulatory capacity of DCs (A, left). DCs of controls, HCV and SVR individuals were analyzed as above (A, right). Control DCs, DCs generated for 7 days with IFN-λ, and DCs exposed to IFN-λ only during the last 24 hrs on day 6, were included in MLR. Incorporation of ³H-Td during the last 16 hours of MLR, read as cpm, was considered indicative of stimulatory capacity of DCs (B). Normal monocytes were transfected with scrambled or IFN-λR-specific siRNA and analyzed for the content of IFN-λR-coding RNA 72 hours later by RT-qPCR, as described in Methods. Fold change compared to mock-transfected cells was calculated from n = 3 sets of experiments (C). Normal monocytes were transfected as above, exposed to IL-4⁺GM-CSF in the presence or absence of IFN-λ for 7 days and included in MLR with normal T cells. T cells alone and DCs alone were used as controls of non-specific proliferation. Incorporation of ³H-Td during the last 16 hours of MLR, read as cpm, was measured as indicative of stimulatory capacity of DCs from n = 5 (D). Total RNA was extracted from MLR co-cultures corresponding to those described in panel D and the content of FoxP3-coding mRNA was analyzed using RT-qPCR, as described in methods. Fold change compared to scrambled MLR which used siRNA-exposed DCs as control was calculated from n = 5 sets of experiments (E). T cells of control healthy individuals were treated with IFN-λ for 5 days, after which they were washed extensively and co-cultured in MLR with dendritic cells which were generated with IL-4⁺GM-CSF without IFN-λ (IFN-λ-naïve) for 4 days. There was no IFN-λ present during MLR. Incorporation of ³H-Td during the last 16 hours of MLR, read as cpm, was measured as indicative of stimulatory capacity of DCs from n = 5 sets of experiments (F). * indicates p<0.05 compared to controls.