IL-10 is not involved in the differential regulation of IFNγ-induced IL-12p40 production by IL-29 and IFNα in human monocyte-derived macrophages on R848 stimulation. Monocyte-derived macrophages were pretreated with IL-29 or IFNα for 5 hours, and then further stimulated with IFNγ and R848. Anti–human IL-10 receptor antibody (αIL10R, 5 μg/mL) was added to some conditions to block the IL-10 receptor. The level of IL-12p40 in the supernatants was determined by ELISA. The values depicted show representative data from 3 independent experiments.