PURIFICATION AND CHARACTERIZATION OF HUMAN NEPHRITOGENIC ANTIGEN THATINDUCES ANTI-GBM NEPHRITIS IN RATS

Human nephritogenic antigen induces anti-glomerular basement membrane antibody glomerulonephritis in rats. This antigen was purified from co llagenase-solubilized renal basement membrane by means of gel filtrati on and affinity chromatography using a rabbit antibody. Western blots of the purified nephritogenic antigen using epitope-defined monoclonal antibodies showed that it contains the NCl domains of the alpha 1 to alpha 6 chains of type IV collagen. Nephritogenicity was thought to be a feature of the NCl domains of the alpha 3 to alpha 5 chains, becaus e the alpha 6 chain is not located in the glomerular basement membrane , and because an NCl fraction consisting of the NCl domains of the alp ha 1 and alpha 2 chains was poorly nephritogenic. Autoantibodies in th e sera of patients with Goodpasture's syndrome were detected by ELISA using the purified nephritogenic antigen. These results indicate that the nephritogenic antigen contains the Goodpasture antigen, defined as the antigen reactive with sera from patients with Goodpasture's syndr ome. (C) 1997 by John Wiley & Sons, Ltd.