Tamm—Horsfall protein

The first is glycosaminoglycan, a compound produced by the body that coats the epithelial cells of the bladder. This compound essentially separates the bladder from the urine by forming a protective layer against bacterial adhesion.14 A second compound known as Tamm-Horsfall protein is secreted into the urine, and prevents E. coli from binding to receptors present on the surface of the bladder. Other factors implicated in contributing to host defense mechanisms include immunoglobulins, specifically IgA, and lactobacilli, bacteria that are part of the normal vaginal flora.13,15... 

Uto, I., Ishimatsu, T., Hirayama, H., Ueda, S., Tsuruta, J., and Kambara, T. (1991) Determination of urinary Tamm-Horsfall protein by ELISA using a maleimide method for enzyme-antibody conjugation. J. Immunol. Meth. 138, 87-94. 

Several sulfotransferases probably occur in a given tissue.353,362 Presumably, sulfation of the glycoproteins found in the digestive tract (see Table II, p. 412) occurs by a similar mechanism, in which 3 -0-phosphono-5 -adenylyl hydrogen sulfate is the donor. Neither the origin of, nor the acceptor site for, the sulfate group reported to occur in human Tamm-Horsfall protein is known.363,364... 

Urinary casts, often excreted by patients having renal disease, possess414 antigenic determinants in common with the Tamm-Horsfall protein (see p. 414), and, indeed, this glycoprotein is the major component of the casts.414-416 However, the reason for its aggregation is as yet unknown. Other pathological states may well be found to be associated with abnormalities in the structure or metabolism, or both, of glycoproteins. 

Immunoassays for Bik, based on polyclonal antibodies (pAb), are affected by cross-reaction with Tamm-Horsfall protein (THP). This problem can lead to the generation of false positive results in cases of proteinuria [14], In contrast, immunoassays that utilize plasma suffer from cross-reactivity to Iof [23]. The cross-reactivity with THP is due to complexed N-linked glycan, whereas cross-reactivity with Iof is due to bound Bik [14]. Cross-reaction with a-1-glycoprotein (AGP) also does not appear to be a significant factor in blood. 

Worcester EM, NakagawaY, WabnerCL, Kumar S, Coe EL. Crystal adsorption and growth slowing by nephrocalcin, albumin, and Tamm-Horsfall protein. Am.J.Physlol. 1888 255 F1179-F1205. 

In addition, the proportions of individual proteins excreted in the urine depend on the extent of their reabsorption by the proximal renal tubules, which is also inversely proportional to molecular size. The reabsorption of low molecular weight proteins involves binding of the protein to specific receptors on the tubule epithelial cells, uptake into the cells by pinocytosis, fusion of uptake vacuoles with lysosomes, and hydrolysis of the protein by lysosomal enzymes, followed by return of the constituent amino acids to the body pool. Very little of the total excreted urinary protein normally consists of small proteins. Only a small amount of protein is excreted normally (20 to 150mg/dL), and most of it is albumin because of its concentration—it is not completely removed from the filtrate by the tubular cells. The remainder is almost entirely the Tamm-Horsfall protein uromucoid, a constituent of urinary casts, probably secreted by the distal tubules. 

Hoyer JR, Seiler MW. Pathophysiology of Tamm-Horsfall protein. Kidney Int 1979 16 279-89. 

Orskov 1, Ferencz A, Orskov F. Tamm-Horsfall protein or uromucoid is the normal urinary sUme that traps type-1 fimbriated Escherichia coli. Lancet 1980 1 887. 

Marengo, S. R., Chen, D. H., Kaung, H. L., Resnick, M. L, and Yang, L. (2002). Decreased renal expression of the putative calcium oxalate inhibitor Tamm-Horsfall protein in the ethylene glycol rat model of calcium oxalate urolithiasis. J Urol 167, 2192-2197. 

Occupational exposure to Hg vapors Tamm-Horsfall protein, tubular antigen Cardenas et al. 1993 ... 

Devuyst, O., K. Dahan, and Y. Pirson. 2005. Tamm-Horsfall protein or uromodulin New ideas about an old molecule. Nephrology, Dialysis, Transplantation 20 1290-1294. 

Gokhale, J. A., P. A. Glenton, and S. R. Khan. 1997. Biochemical and quantitative analysis of Tamm-Horsfall protein in rats. Urology Research 25 347-354. 

A two- to three-fold increase in Na -K -ATPase activity, a nonspecific marker a three-fold reduction in a negative marker, alkaline phosphatase identified with proximal tubular cells and immuno-fluorescent localization of Tamm-Horsfall protein, a specific marker for mTALH cells. 

Nephrogenic proteinuria. This includes renally derived proteins, e.g. Tamm-Horsfall protein or immunoglobulins, which can be secreted into the urine in increased amounts in nephritis. 

Glycosaminoglycans (heparin sulphate), Tamm-Horsfall protein (THP) (Hess et al. 1991), nephro-calcin, and uropontin are other potent inhibitors of crystallization processes (Ryall 1996). However, their physiological role, if any, is disputed. The role of THP as inhibitor must be distinguished from the so-called THP kidneys, which can be seen in the first 5 days of life in neonates (Fig. 20.15) (Avni et al. 1983 Berdon et al. 1969 Starinsky et al. 1995). 

Saemann MC, Weichhart T, Horl WH et al (2005) Tamm-Horsfall protein a multilayered defence molecule against urinary tract infection. Eur J Clin Invest 35 227-235... 

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