Characterization and Isolation of Specific Renal Tubular Epithelial Antigens

Two renal tubular epithelial specific antigens were found to be membrane-bound and localized to the brush border of cells of the proximal convoluted tubules of the rat. Cross-reacting or identical antigens were also identified in the brush border of the small bowel mucosa. Both antigens were isolated biochemically and one was highly purified. One antigen, renal tubular epithelium (RTE)-α4, appears to be a lipoprotein, so20w of 28S, and the other a protein, so20w of 9.8S. RTE-α3 is immunogenic but is masked in situ so that direct interaction with humoral antibody does not occur. This antigen does appear in the serum following tubular epithelial injury. Neither of the isolated RTE-specific antigens is the pathogenetic antigen responsible for experimental allergic glomerulonephritis induced with tubular antigen.