R-848 leads to the induction of adhesion molecules on endothelial cells in vitro, and endothelia in situ express TLR7. (A) Confluent layers of the murine endothelial cell line BEnd5 were stimulated with R-848, PBS, or TNF-α for 4 hours and subsequently stained for the expression of the indicated adhesion molecules in the tissue culture. Red indicates adhesion molecules; blue, cell nuclei (DAPI [4,6 diamidino-2-phenylindole]). Bar indicates 25 μm. Data were comparable in 2 independent experiments. (B) Expression of TLR7 (gray peak) on BEnd5 cells and naive splenic B cells, which are known to express TLR7, as analyzed by flow cytometry. The white peak indicates the isotype control staining. (C) Coexpression of CD31 and TLR7 on endothelial cells of spleen tissue.