LECTIN-BEARING POLYMERIZED LIPOSOMES AS POTENTIAL ORAL VACCINE CARRIERS

Purpose. The potential of using lectin-modified polymerized liposomes as Peyer's patch targeted oral delivery vehicles was examined. Methods , Two types of lectins, Ulex Europaeus Agglutinin I (UEA I) and Wheat Germ Agglutinin (WGA), were modified with a hydrophobic anchor N-gluta ryl-phosphotidylethanolamine (NGPE). The modified lectins were incorpo rated into liposome bilayers and the liposomes were subsequently stabi lized through polymerization. The presence of the lectins on the lipos ome surfaces was first confirmed with X-ray photoelectron spectroscopy . Surface-immobilized lectins were then shown to retain their carbohyd rate binding activities as well as specificities based on an in vitro aggregation assay. Finally, delivery efficiencies of lectin-bearing li posomes were determined in mice. Results. About 10.5% UEA I liposomes and 5.8% WGA liposomes were taken up from the gastrointestinal tract. These numbers are significantly higher than the 3.2% observed in the c ase of lectin-free liposomes. At the same time, UEA I liposomes exhibi ted the most effective Peyer's patch targeting among the three, which directly correlated with the highest delivery efficiency observed. Con clusions, This establishes that lectin modification of liposomes can p romote binding to Peyer's patches, which will give improved efficiency for Peyer's patch targeted delivery. All these point to the potential for these lectin-modified liposomes as novel vehicles for oral vaccin ation.