Electron microscopic autoradiographic study on immune complex formation in rat glomerulus with anti-heparan sulfate proteoglycan antibody

Using electron microscopic autoradiography, we studied the mechanism of the formation of immune complex in the subepithelial aspect of glomerular basement membrane in rats, as a model for glomerulonephritis in man. Rats were immunized with normal rabbit IgG, and were administered intravenously with radioiodinated rabbit anti-heparan sulfate proteoglycan (HS-PG) antibody. Two weeks later the center of the grains appeared to correspond with the center of the subepithelial electron dense deposits, thus suggesting a topological superimposition of the radioiodinated anti-HS-PG antibody over the immune complex deposits located in the subepithelial space. From our present study it has become clear that the HS-PG site may serve as the corenidus for the formation of immune complex deposit. Electron microscopic autoradiography is very helpful in the demonstrating of in situ immune complex formation in glomerulonephritis.