LNDCs infiltrate mIFRs and acquire viral antigen. (a) Schematic diagram of the architecture of a PLN. mIFRs and cIFRs are highlighted in red and blue, respectively. (b) Confocal imaging of mIFRs in CD11c-eYFP PLNs 40 min after vaccination with PBS or UV-PR8. Blue arrowheads: CD8a⁺ DCs; red arrowheads: CD11b^hi DCs. Images are representative of three independent trials; three mice/trial. B, follicles; M, medulla; T, T cell cortex. (c) Reconstructions of in vivo–labeled C57BL/6 PLNs vaccinated with A633–UV-PR8 and collected at 0.5 or 6 h after injection. White arrowheads: IFRs. SS, subcapsular sinus. Images are representative of three independent experiments; two mice per time point per experiment. (d) MPM of in vivo–labeled CD11c-eYFP PLNs 60 min after PBS or A633–UV-PR8 vaccination. Dashed lines: IFRs. Images are representative of four independent experiments; two mice per experiment. (e) LNDC capture of A488–UV-PR8 by flow cytometry 60 min after injection. (left) Cells displayed are pregated to be CD11c^hi (n = 4 PLNs). Mean ± SEM. (f) MPM of in vivo–labeled CD11c-eYFP PLNs 6 h after A633–UV-PR8 vaccination. White arrowhead: UV-PR8 patch on the LNDC. Image is representative of four independent experiments; two mice per experiment.