BINDING AND INTERNALIZATION OF FLUORESCEINATED CONCANAVALIN A BY ENDOTHELIAL CELLS FROM NORMAL AND FABRY HEMIZYGOUS UMBILICAL VEINS

It was shown that concanavalin A is bound to the surface of cultured human endothelial cells and subsequently taken up by the cells. The cell lines were established from the endothelium of umbilical veins and included normal cell lines and a line from a fetus hemizygous of Fabry disease. The Fabry cell line was deficient in α-galactosidase. A. Fluorescein-conjugated concanavalin A was bound to the cells at 4°C, and a redistribution of the lectin started shortly after the temperature was raised to 37°C. Clusters and polar minicaps appeared within 10 to 30 min; after internalization the fluorescence accumulated in the perinuclear regions. It has previously been shown that a concanavalin A-mediated uptake of different lysosomal enzymes occurs in fibroblasts. The present results indicate that it may be possible to use the same method for uptake of purified enzyme, e.g. α-galactosidase A, in endothelial cells grown in vitro.