Synthetic glycolipids: Interaction with galactose-binding lectin and hepatic cells

Lactosyl- and melibiosyl-phosphatidylethanolamine prepared by reductive animation with sodium cyanoborohydride were incorporated into small unilamellar liposomes. Lactosyland melibiosyl-phosphatidylethanolamine liposomes are aggregated by Ricinus communis agglutinin whereas Banderiaea simplicifolia isolectin I aggregates only melibiosyl-phosphatidylethanolamine liposomes. The association constant (K_a) values of interactions of R. communis agglutinin and glycolipids were 5 × 10⁵ and 1.2 × 10⁵m^?1 for lactosyl- and melibiosyl-phosphatidylethanolamine, respectively, whereas the K_a for the interaction of B. simplicifolia isolectin I for melibiosyl-phosphatidylethanolamine was found to be 6 × 10⁵m^?1. The rates of aggregation of these liposomes are strikingly influenced by the amount of glycolipid incorporated into them. In vivo studies indicate that lactosyl-phosphatidyl-ethanolamine-containing liposomes are rapidly taken up by hepatic cells due to binding of their β-d-galactopyranosyl residues by the hepatic galactose-binding lectin.