The electron microscopic localization of nephrotoxic antibodies in isolated glomeruli.

Scanning electron microscopy showed that most glomeruli isolated by sieving from normal and nephrotoxic rats were cleanly decapsulated and undisrupted. An anti-IgG antibody-horesradish peroxidase conjugate was applied to such isolated glomeruli and also to slices of renal cortex which were sebsequently embedded in epoxy resin. Linear staining along the glomerular basement membranes of nephrotoxic rats was evident and subendothelial electron-dense deposits were shown to contain anti-glomerular basement membrane antibody. Whereas the linear reaction was faint and limited to superficial parts of glomeruli in tissue slices, it was intense and present in most regions of all of the isolated glomeruli. Thus, the fine details of the distribution of intraglomerular antibody are more clearly and consistently demonstrated in isolated glomeruli than in kidney slices.