TAMM-HORSFALL PROTEIN - DIFFERENTIAL EFFE CT ON FIMBRIAL ADHERENCE OFESCHERICHIA-COLI TO RENAL TUBULAR EPITHELIAL-CELLS

Many factors increase pathogenicity of uropathogenic Escherichia coli. Among them, fimbriae play a major role, since these protein appendice s contribute towards bacterial adhesion to uroepithelial cells. In cli nical Escherichia coli isolates from urinary tract infections, P fimbr iae are more frequently present than S fimbriae, though both types of fimbriae mediate adhesion to cultured tubular epithelial cells equally well. The incongruity between clinical relevance and adherence capaci ty led to the hypothesis that there is an urinary factor which inhibit s S fimbrial but not P fimbrial adherence. Tamm-Horsfall protein, whic h is produced in cells from the loop of Henle and the distal tubule, i nhibits hemagglutination by S, but nor P fimbriated Escherichia coli. We examined the effect of Tamm-Horsfall protein on fimbrial adherence of Escherichia coli to tubular epithelial cells and found adherence of S and P fimbriated Escherichia coli significantly reduced. The effect was specific and dose-dependent. In conclusion, these data may explai n the low clinical relevance of S fimbriaeted Escherichia coli, but no t the predominance of P fimbriated.