ALDH activity is moderately affected by in vitro TLR triggering and by in vivo MCMV infection. (A-B) CD11c⁺ DCs were purified from spleen (A) and MLNs (B) using MACS isolation and cultured in the presence or absence of zymosan (10 μg/mL), lipopolysaccharide (1 μg/mL), or CpG (5μM). After 18 hours of culture, cells were incubated with ALDEFLUOR and analyzed by flow cytometry. Histograms show the percentages of ALDH⁺ cells found in the specified subsets. Data correspond to mean ± SD of 3 separate experiments. The values corresponding to unstimulated and TLR-stimulated cultures were subjected to statistical comparison. *P < .05. (C-G) Mice were infected with 5 × 10⁴ PFU of MCMV. Light-density cells from the spleen of noninfected (C) or mice infected for 2 days with MCMV (D) were incubated with ALDEFLUOR and analyzed by flow cytometry for CD11c, CD8α, and CD11b expression and ALDH activity. Positioning of the ALDH⁺ gate is based on incubation in the presence of DEAB (not shown). Dot plots correspond to conventional DCs of individual animals, and numbers in outlined areas indicate percentage of cells. The percentage of ALDH⁺ cells within the cDCs (E), the percentage of Foxp3⁺ cells within the CD4⁺ T cells (F), the total number of Foxp3⁺ T cells per spleen (G), and the viral load present in spleens (H) are shown at different time points after infection. Time point “0” corresponds to noninfected control mice. Data correspond to mean ± SD of at least 2 separate experiments per time point. The values corresponding to noninfected and MCMV-infected mice were subjected to statistical comparison. *P < .05.