Enhancement of in situ immune complex formation in isolated perfused kidneys in Heymann's nephritis

A preparation of the putative antibody of HN (Heymanns' nephritis) lacking performed immune complexes, obtained from the acid eluates of kidneys with HN, purified through ion exchange and gel-filtration chromatography, characterized by immunoelectrophoresis, sucrose density-gradient ultracentrifugation, ¹²⁵I-C1q assay for immune complexes, and specific for the brush border of rat proximal renal tubule was injected intravenously, intra-arterially directly into the left renal artery of a kidney with intact normal circulation, and into the isolated buffer-perfused kidney, respectively, in three groups of rats. Controls were injected with non-antibody IgG, and antibody absorbed with the specific antigen. Localization of antibody was studied by direct immunofluorescence. Prompt localization of antibody and formation of in situ immune complexes occurred in the isolated perfused kidney. No localization of antibody was seen following the intrarenal arterial injection in the unperfused kidney with intact circulation, and a delay of 5 days was noted for the localization to develop upon intravenous injection. These results show that, in the homologous antibody-induced HN, the preparation of isolated perfused kidney considerably enhances the formation of in situ immune complexes in glomeruli as compared to the unperfused kidney with intact circulation in which the antibody is injected either directly into the renal artery or systemically through a peripheral vein.