IL-12 acts directly on DC to promote nuclear localization of NF-κB and primes DC for IL-12 production

We analyzed the expression of an IL-12 receptor by fresh dendritic cells (DC) and a DC line. Using RT-PCR, RNAse protection, and electrophoretic mobility shift assay analysis, we found that DC possess an IL-12 receptor with beta 1 subunit (downstream box 1)-related differences from that on T cells. IL-12 signaling through this receptor involved members of the NF-kappa B but not STAT family. The unique properties of the IL-12 receptor on DC, characterized by a single class of binding sites with a K-d of about 325 pM, may underlie rather unique effects, such as IFN gamma-independent augmentation of class II antigen expression and priming for LPS-induced production of IL-12.