Adherence of uropathogenic E. coli to differentiated human uroepithelial cells grown in vitro

A quantitative in vitro model to measure E. coli adherence to differentiated human uroepithelial cells has been developed. Primary cultures of uroepithelial cells were initiated from normal ureteral epithelium. Adherence of uropathogenic 3H-labelled Escherichia coli to postconfluent human uroepithelial cells was directly related to the bacteria:epithelial cell ratio during incubation. Bacterial attachment was inhibited either by mannose or by urine containing anti-E. coli antibodies. Transmission electron microscopy showed that epithelial cells differentiated in vitro to resemble normal uroepithelium in vivo. Furthermore, electron microscopy showed specific adherence of bacteria to the glycocalyx of microvilli of the superficial uroepithelial cells in vitro in a manner which closely mimics the in vivo interaction. This model of bacterial adherence permits in vitro analysis of adhesin-receptor interactions between uropathogenic E. coli and a layer of viable uroepithelial cells similar to those lining the bladder.