Local depletion of DCs interferes with BALT maintenance. Mice expressing DTR under the control of the CD11c promoter (CD11c-DOG) were infected twice with 107 IU MVA. On days 8 and 10, mice were treated i.n. with 50 ng DT (+DT) or with PBS (−DT). (A) Lung sections from DT-treated or untreated mice stained with DAPI and anti-CD11c. Bar, 200 µm. (B) Micrographs were quantitatively analyzed for the presence of anti-CD11c signals. (C) No change in the percentage of DCs in the mesenteric LNs was detected by flow cytometry. Pooled data from three experiments, each with one to two mice per group, are shown. (D) The number and size of individual BALT structures from DT-treated or untreated mice were determined on large composite images of entire lung sections (n = 6 mice /group in B and D with two to three lung sections per mouse in two independent experiments analyzed). Symbols represent the mean BALT size per lung, and red bars represent means. ***, P < 0.001.
