Fig. 1.

Toll-like receptor 2 (TLR2) is expressed in the basolateral membrane domain of the medullary thick ascending limb (MTAL). MTALs dissected from rats (A–C) and from wild-type (D) and TLR2^−/− (E) mice were stained with anti-TLR2 antibody and analyzed by confocal immunofluorescence as described in methods. B: merged differential interference contrast image of the tubule in A to establish cell boundaries for the TLR2 localization. Images are z-axis sections (0.4 μm) taken through a plane at the center of the tubule, which shows a cross-sectional view of cells in the lateral tubule walls (33, 81). TLR2 staining was observed selectively in the basolateral membrane domain. The TLR2 staining was absent in the presence of blocking peptide and in MTALs from TLR2^−/− mice. Images are representative of at least 4 tubules of each type. Scale bar = 5 μm.