The detection and characterization of renal brush border antigen (gp108) in various rat tissues.

We recently reported that an injection of antibody raised against renal brush border glycoprotein, gp108, in rats induced passive Heymann nephritis with acute and severe proteinuria. In this study, the distribution of gp108 in various rat tissues was investigated. On enzyme immunoassay, anti-gp108 antibody reacted to extracts of small intestine, lung, spleen, thymus, liver, epididymis, stomach, pancreas and heart. It also reacted to sera and extracts of peripheral blood cells, especially lymphocytes. These antigens, which are cross-reactive to kidney gp108 have similar biochemical properties: a molecular weight of about 108,000 and an isoelectric point of 4.8-5.4. These results show that immunologically and biochemically related antigens to renal glycoprotein, gp108, are present in various rat tissues.