Fig. 4.

CX₃CR1⁺ CD8α⁺ DC share expression profile, somatic Ig gene rearrangements, and E2-2 dependence with PDC. (A) PCA of the genes overexpressed in CX₃CR1⁺ CD8α⁺ cells compared with CD8α⁺ cDC. Shown are the three principal component sets of genes analyzed against the expression data of Robbins et al. (35). Note the preferential expression in PDC (Top), in CD8α⁻ DC (Middle), and in both PDC and CD8α⁻ DC (Bottom). (B) Distribution of genes specific for CD8α⁺ DC or PDC in the two CD8α⁺ DC subsets. Shown is pairwise comparison of average probe intensities in CX₃CR1⁺ and CX₃CR1⁻ CD8α⁺ DC; genes specific for CD8α⁺ DC or PDC were selected based on reference 35. (C) IFN-α production by sorted splenic DC subsets after incubation for 20 h in the presence or absence of 400 HAU/mL influenza virus. (D) Expression of the TLR/IFN signaling genes in sorted CD8α⁻ cDC, PDC, and CX₃CR1⁺ CD8α⁺ DC as determined by quantitative RT-PCR (mean ± SD of triplicate reactions). Expression levels are normalized relative to the CX₃CR1⁺CD8α⁺ subset. (E) D–J rearrangement of IgH gene in sorted DC subsets. IgH D–J rearrangements were detected by genomic PCR using primer sets for the D_HQ52 element. Data are representative of three experiments. (F) Absence of CX₃CR1⁺ CD8α⁺ DC and PDC in absence of the transcription factor E2-2. (Left) Gated donor-derived (CD45.2⁺) splenocytes from E2-2^−/− chimeras or control E2-2^+/+ chimeras mice were analyzed for the presence of CD11c^int Bst2⁺ PDC. (Right) Gated CD11c^hi CD8α⁺ DC comprise the CD86^lo SSC^lo and the CD86^hi SSC^hi subsets (corresponding to CX₃CR1⁺ and CX₃CR1⁻ populations, respectively). Data are representative of three independent experiments.