Dominant IFN gene transcription in pDCs after viral activation. (A-B) Purified pDCs were cultured with HSV-1, and cells were collected at different times after stimulation; mRNA expression of IFN-α and IFN-β were then examined by RT-PCR (A) and real-time quantitative PCR (B). (C) Suppression subtraction hybridization was performed with total RNA prepared from purified human pDCs activated with IL-3 and HSV-1, and from cells incubated with only IL-3 for 6 to 8 hours. Percentages of transcripts for IFN-α (121 sequences), IFN-β (5 sequences) and IFN-ω (29 sequences) within 258 random sequences are indicated. (D-E) Expression profiles of the type 1 and 2 IFN family genes in the DCs were analyzed by microarray (D) and real-time quantitative PCR (E). Each graph represents data from pDCs and CD11c⁺ mDCs, either resting or activated by virus or TLRL for 20 hours. Results of the gene expression profiles (D) are shown as relative hybridization intensity levels in the microarray analysis. Flu indicates influenza virus.