The development of a radioimmunoassay for Tamm–Horsfall glycoprotein in serum

Abstract

The Tamm-Horsfall glycoprotein prepared by salt precipitation from urine was found to comprise a heterogeneous collection of aggregates. These could be disaggregated with 8m-urea, following which chromatography on a column of Bio-Gel A.15m yielded a homogeneous glycoprotein of mol.wt. 73000 together with several unidentified impurities. Gel filtration of normal plasma showed the glycoprotein to exist predominantly in a form that is eluted identically with the purified preparation. In one case, material of higher molecular weight was also detected. The purified glycoprotein was used to develop a rapid specific radioimmunoassay for its measurement in human serum or plasma by the use of the Tamm-Horsfall glycoprotein, labelled with (125)I by the chloramine-t method as the tracer, an antiserum raised in rabbits, and separation of the bound and free fractions by a second antibody covalently linked to magnetizable particles. Parallelism was demonstrated between the standard preparation and samples. Recovery of added standard to serum varied between 99 and 109%. Total assay time was less than 4h with an intra-assay and inter-assay coefficient of variation of less than 10%. There were no significant differences in the ranges covered with regard to either age or sex, and no circadian rhythm was observed in normal subjects. A physiological range of 70-540ng/ml was established based on serum samples from 95 subjects with normal renal function, as defined by their serum creatinine and urea concentrations. No Tamm-Horsfall glycoprotein was detected in the serum of six anephric patients.

Serum Tamm-Horsfall Protein Levels in Childhood: Relationship with Age and Glomerular Filtration Rate

“…It was originally isolated from human urine by Tamm and Horsfall who noted its ability to inhibit viral haemagglutination [1]. It is present in large quantities in the urine and is also found in plasma where its presence has been demonstrated by Avis [2] using a radio-immunoassay and confirmed by Dawnay et al [3]. It is the major constituent of hyaline casts [4] and is present in the matrix of most types of renal calculi [5].…”

Tamm-Horsfall Protein Excretion during Chronic Alterations in Urinary Concentration and Protein Intake in the Rat

“…A competitive liquid-phase ra dioimmunoassay was used. Rat THP was iodinated us ing the chloramine-T method as described elsewhere [3] for human THP. The assay buffer contained 0.052 M phosphate, 0.01 M EDTA.…”

“…Tamm-Horsfall glycoprotein (THP) has been detected in urine [1], serum [2][3][4] and kidney [5][6][7][8] of a variety of mammalian spe cies. Excreted at a daily rate of 50-100 mg in man, it is the most abundant urinary protein [9].…”

Serum Tamm-Horsfall Glycoprotein Level in Children with Various Renal Diseases

“…We developed an ELISA for the microdetermination of THGP. This assay required no special equipment and safely handled many samples at the same time with the same sensitivity as that of radioim munoassay described by Avis [5] and Dawnay et al [6], Recently, Avis [10] and Hunt et al [11] reported ELISA techniques for the quantitation of serum THGP using a different type of antigen assay. In the present study, our assay had approximately the same sensitivity as their ELISA methods making it useful for determining THGP levels in routine blood samples.…”