IRF7 and infection: In addition, expression of IRF-7, a key IFN-α transcription factor that is induced in pDC upon HIV stimulation [32], [44], was markedly upregulated in iSIV-stimulated blood pDC from untreated macaques at day 0 but not at day 14 post infection, and was not upregulated in pDC from DV056-treated macaques at either time, consistent with both virus- and drug-induced inhibition of pDC responses (Figure 4B).