Analysis of the Heymann nephritogenic glycoprotein in rat, mouse, and human kidney

Passive Heymann nephritis is induced in rats by intravenous administration of antiserum raised against antigens of the renal proximal tubule. Evidence by Kerjaschki and Farquhar indicates that the critical nephritogenic is a high molecular weight glycoprotein (HMWgp) of rat renal brush border membrane. Their immunocytochemical studies also localize the nephritogenic antigen to the glomerular epithelial cell surface and may explain in situ formation of immune complexes at this locus in Heymann nephritis. We have confirmed the observations of Kerjaschki and Farquhar by demonstrating the HMWgp in extracts of rat brush border membrane and isolated glomeruli on sodium dodecyl sulfate-polyacrylamide (SDS-PA) (5%) gels. An antiserum raised to purified rat HMWgp identifies the antigen from rat or mouse kidney on Western blots. However, unlike rodent kidney, we were unable to detect a comparable HMWgp in extracts of human kidney on SDS-PA gels and found no cross-reactive material on Western blots of human brush border membrane proteins. Our observations suggest that human kidney lacks the nephritogenic antigen critical to initiation of Heymann nephritis in rodents.