Modulation of innate and adaptive immune responses by herpesvirus-activated pDCs. pDCs are able to sense infection with herpesviruses through TLR9 and/or TLR7. The triggering of these receptors in specialized endosomes, where they are preassembled with the MyD88 adapter molecule and the IRF7 transcription factor in multimolecular complexes, leads to the phosphorylation of IRF7 and its translocation to the nucleus where it associates with other partners to constitute a transcription initiation complex (TIC) able to induce the expression of IFN-I and other target genes. Largely due to their production of innate cytokines or chemokines, pDCs can exert a variety of stimulatory or inhibitory functions on other innate or adaptive immune cell types. The global effect of pDC responses on the overall immune response and on the promotion of health versus disease depends on the combination and levels of the cytokines that they produce as discussed in Scheme 2.