Ultrastructural localization of human kidney antigens using monoclonal antibodies.

A highly sensitive method of ultrastructural-immunoperoxidase staining was developed for use with monoclonal antibodies which have been raised in this laboratory to a variety of antigens of the human kidney. Because of the susceptibility of the antigens to fixation and processing, a four layer, pre-embedding method of staining was used. Results confirmed and clarified previously reported light microscopy results, indicating that an antigen recognized by the PHM5 antibody was found on the podocyte cell membrane within the glomerulus and was not present within the glomerular basement membrane. The antigen was also present on the extraglomerular endothelial cell membrane. The study also demonstrated the presence of an antigen specific to endothelial cells throughout the renal cortex, and gave further insight into the precise localization of glomerular basement membrane components including fibronectin. The method of staining is now being used together with detailed ultrastructural studies to identify the cells produced from isolated glomeruli in tissue culture.