SEW2871 treatment results in B and T lymphocyte but not pDC accumulation in the LNs, and pDCs are found in the cortical sinusoids of SEW2871-treated mice. (A) C57Bl/6 mice were treated with SEW2871 to prevent S1P1-mediated egress. B cells, T cells, and pDCs were quantified in 6 pooled LNs versus 1 mL blood, and the numbers were used to generate a ratio of cells in LN/blood. The experiment was performed 3 times with similar results. *P < .05. (B) LNs from SEW2871-treated mice were frozen, sectioned, and stained for immunofluorescence microscopy. Images were obtained using a ×20 objective. LNs from 3 representative mice are shown from a collection of 6 different mice. Arrows indicate close associations between PDCA-1–positive cells and LYVE-1 cortical sinusoids.