Reduction in the anti-adherence activity of Tamm-Horsfall protein with increasing concentration of calcium.

Tamm-Horsfall glycoprotein (THP), at concentrations occurring in normal urine, was demonstrated to show anti-adherence activity for type-1 fimbriated Escherichia coli. Urine also showed anti-adherence activity, and urine from which the THP was precipitated showed a significant drop in activity. The addition of calcium to the incubation medium with THP, at concentrations normally found in the urine, had no effect on the anti-adherence activity of THP. However, concentrations of calcium higher than those normally occurring in the urine significantly decreased the anti-adherence activity of THP. It is suggested that individuals with above normal concentrations of calcium in the urine may be at increased risk for urinary tract infections since the protective effect of THP is compromised.