Effects of IFN-α on pDCs in vivo. C57BL/6 mice were injected intravenously with pORF vector or pORF encoding GM-CSF (GM, 5 μg), IFN-α (IFN, 3 μg), or a combination of both plasmids (GM + IFN, 8 μg) by HGT, or left untreated (NT). Four days later, BM and spleens were collected for analysis. (A) ELISA results on sera samples collected at day 4 from mice treated by HGT, as indicated. Data are the mean ± SEM of 8-10 individual samples. (B) Proportion of pDCs (top left quadrant) and cDCs (botom right quadrant) in BM and spleen of mice treated by HGT, as indicated. Results were gated on the CD11c⁺ population (not shown); B220 and CD11b analysis is shown. Data represent 3 independent experiments. (C) Absolute pDC and cDC numbers in BM (2 femurs + 2 tibias) and spleen of mice treated by HGT, as indicated. n = 8 to 10 (3 independent experiments). Error bars represent SEM. (D) IFN-α production from pDCs sorted by FACS from BM of HGT-treated mice on CpGA stimulation. Error bars represent SEM of 8 to 10 individual samples. (E) Numbers of DC progenitors (lin⁻ Flt3⁺ cells) in mice treated by HGT, as indicated. n = 6 (2 independent experiments). Error bars represent SEM.