FV infection of myeloid DCs in vitro and in vivo. Myeloid DCs were generated from the BM of FV-infected BALB/c mice and analyzed for viral infection. (A) CD11c-gated DCs were stained for FV glycosylated Gag protein using mAb 34. A flow cytometric analysis representative for more than 20 independent DC cultures is shown (mean, 21.2% ± 0.8%). The mean percentage of positive cells (FV-infected cells) is given in the top right quadrant. (B) Electron microscopy picture of virus particles in an infected DC. Virus particles are visible as numerous small electron-dense bodies at the margin of the cytoplasm (). Transmission electron microscopy; original magnification, ×28 000. See “Analysis of cell-cell interactions within 3D collagen gels” for complete image acquisition information. (C) FV-induced splenomegaly in BALB/c mice at 2 weeks after transfer of 3.5 × 10⁵ infected DCs (right). (D) Quantification of infected DCs using M dunni cells. A total of 1 × 10⁵ DCs were cocultivated with the indicator cells, which were subsequently stained for infectious centers (ICs). Representative results for more than 5 independent experiments are shown. The uninfected DCs were generated from naive mice. (E) Myeloid DCs were isolated from the spleen of FV-infected BALB/c mice and analyzed for viral infection directly ex vivo. CD11c-gated DCs were stained for FV glycosylated Gag protein using mAb 34. A flow cytometric analysis representative for 5 individual mice is shown (mean, 22.3% ± 1.5%). The mean percentage of positive cells (FV-infected cells) is given in the top right quadrant.