Figure 5.

Exfoliation of bladder epithelial cells. (A) The luminal surface of the bladder is normally covered by extremely long-lived, highly differentiated superficial facet cells with distinctive pentagonal or hexagonal outlines. These large cells (ranging from 20 to 150 μm in diameter) are often bi- or multinucleate and can be easily identified on the surface of whole-mount bladders stained with Hoechst dye. (B) Within 6 h after inoculation with type 1-piliated E. coli, many infected facet cells in C57BL/6 mice exfoliate and are rinsed away, revealing the smaller, mono-nucleate underlying epithelial cells. (C) A stained paraffin section from an infected mouse bladder shows a facet cell in the process of exfoliating and taking a large mass of adherent E. coli with it. Host cell nuclei were stained with Hoechst dye whereas bacteria were stained red by using anti-E. coli primary and Cy3-labeled secondary antibodies. [Bars = 100 μm (A and B) and 10 μm (C).]