Studies to assess the biological relevance of anti-Tamm-Horsfall protein antibodies detected by direct-binding enzyme-linked immunosorbent assay.

1. A role has been suggested for anti-Tamm-Horsfall protein (THP) antibodies in renal disease based on the results of immunoassays of pathological sera. The putative autoantibodies have not been isolated from such sera nor have definitive inhibition studies of their binding been carried out.

Relationship of abnormal Tamm-Horsfall glycoprotein localization to renal morphology and function.

Tamm-Horsfall glycoprotein (TH) distribution was studied using a biotin-avidin immunoperoxidase technique in renal biopsies from 166 consecutive patients and 8 normal kidneys. Tubulointerstitial damage was independently assessed and graded. In 109 patients TH antibodies were measured by ELISA and in 30 of these urinary TH and beta 2-microglobulin excretions were measured by radioimmunoassay.

Affinity-purified antibodies of defined specificity for use in a solid-phase microplate radioimmunoassay of human Tamm-Horsfall glycoprotein in urine.

Rabbit antibodies to human Tamm-Horsfall glycoprotein (prepared by salt precipitation from normal urine) were purified by affinity chromatography using columns containing Tamm-Horsfall glycoprotein linked to CNBr-activated Sepharose 4B. The specificity of these antibodies was determined by analysis of their binding characteristics on Western blots of Tamm-Horsfall protein from sodium dodecyl sulphate/polyacrylamide gradient gels and comparison with the reactivity of monoclonal antibodies to this glycoprotein. Optimal conditions of adsorption to poly(vinyl chloride) microtitre plates were established such that these purified antibodies could be used in a solid-phase radioimmunoassay for the determination of urinary Tamm-Horsfall-glycoprotein concentration.