Ultrastructural localization of glycocalyx domains in human kidney podocytes using the lectin-gold technique

The lectin-gold technique was used to reveal Helix pomatia lectin (HPL)-binding sites in human kidney glomeruli. HPL-binding sites were associated mainly with podocyte foot process bases, and extended over the lamina rara externa of the glomerular basement membrane. In addition, kidneys from blood group A1 donors showed labeling of capillary endothelial cells and erythrocytes. After neuraminidase digestion of the sections prior to incubation with HPL-gold complexes, HPL-binding sites appeared on previously negative regions of the glomerulus. This increase in labeling was particularly striking at the level of the podocyte-free surface (adjacent to the urinary space) in all kidneys, and on capillary endothelial cells from donors of blood groups other than A1. These results demonstrate the existence of two distinct glycocalyx domains in human kidney podocytes, and show the application of the lectin-gold technique for the high resolution, ultrastructural detection and quantification of lectin-binding sites in human material