Abstract
Type I and III IFNs are crucial, soluble components of potent antiviral responses. It has been explored recently that mTOR is involved in the regulation of IFN-α/β production by pDCs, albeit its role in the induction of IFN responses in cDCs remained unrevealed. In this study, we demonstrate that the PI3K/mTOR pathway is indispensable for eliciting intact type I and III IFN responses in moDCs stimulated with polyI:C. The inhibition of mTOR functionality by rapamycin impairs the pIRF3 and also a few members of the MAPK family, suggesting that mTOR contributes to the activation of multiple signaling pathways in the presence of viral antigens. Furthermore, rapamycin-treated moDCs show decreased capacity to prime IFN-γ secretion by naive CD8(+) T-lymphocytes. As in moDCs, mTOR-mediated regulation is also essential for the production of type I and III IFNs in circulating CD1c(+) DCs. To our best knowledge, these results demonstrate for the first time that mTOR has an impact on the functional activities of cDCs via modulating the outcome of IFN secretion.