Ultrastructural immuno-gold localization of immune deposits in human renal biopsies.

Ultrastructural immunolocalization of immunoglobulins has the potential to supply new information about immune-mediated glomerulonephritides. Most previous studies have used immunoperoxidase pre-embedding techniques to identify the components of glomerular deposits. These techniques have not been satisfactory as they only allowed the identification of one antigen (immunoglobulin) in each portion of tissue under investigation and also caused obliteration of labelled structures by the dense reaction product. Several studies have used colloidal gold as a post-embedding label, but these have been unable to localize immunoglobulins or complement components in epoxy resin embedded tissue. The present study uses glutaraldehyde-fixed tissue which is embedded in a polar acrylic resin. This technique results in good ultrastructural detail while allowing maximum antigen retention and, when combined with colloidal gold labelling, it provides the optimal procedure for ultrastructural immune localization. A spectrum of immunologically induced renal diseases is examined using this technique, the results of which correlate well with immunofluorescence.