Appearance of Helix pomatia lectin-binding sites on podocyte plasma membrane during glomerular differentiation. A quantitative analysis using the lectin-gold technique.

The visceral glomerular epithelial cells (podocytes) of newborn rat kidneys were examined by the lectin-gold technique to determine the distribution of Helix pomatia lectin-binding sites during glomerular development. Previous work has shown that this lectin, which primarily recognizes terminal N-acetyl-D-galactosamine residues of glycoconjugates (but also N-acetyl-D-glucosamine to a lesser extent), specifically labels the plasma membrane glycocalyx of podocyte foot process bases, whereas the plasma membrane of the podocyte cell body that is in contact with the urinary space is unlabeled. In neonatal glomeruli, the labeling was most intense in those podocytes whose pedicel development corresponded to that seen in adult rat kidneys, whereas immature podocytes were poorly labeled. A quantitative evaluation of the labeling showed a highly significant correlation between the degree of podocyte development (as assessed by counting the number of pedicels per micrometer of basal lamina) and the intensity of H. pomatia lectin-gold particle labeling. These results show that the appearance of pedicels on developing podocytes is accompanied by the appearance of a specific cell coat component(s), detectable using H. pomatia lectin-gold complexes.