Ultrastructural visualization of concanavalin A binding receptor sites in neoplastic and non-neoplastic transitional...

Concanavalin A binding receptor sites in non-neoplastic and neoplastic transitional cell epithelium from tumour-bearing human urinary bladders were mapped ultrastructurally following successive incubation of vibratome slices with concanavalin A, peroxidase and diaminobenzidine. In the normal epithelium the reaction product was found in the plasma membranes of the basal cells. Some areas of the endoplasmatic reticulum and the discoid vesicles were reacting in all cell layers. In the neoplastic epithelium, reaction product was localized to the plasma membranes throughout the epithelium, irrespective of the grade of malignancy. The intracellular distribution was similar to that in normal epithelial cells. The topographical distribution suggests that concanavalin A binding glycoproteins are found in the transitional cell epithelium in immature membranes.