Targeting polymerised liposome vaccine carriers to intestinal M cells

Due to their transcytotic capability, intestinal M cells may represent an efficient potential route for oral vaccine delivery. We previously demonstrated that the lectin Ulex europaeus agglutinin 1 (UEA1, specific for alpha-L-fucose residues) selectively binds to mouse Peyer's patch M cells and targets 0.5 microm polystyrene microparticles to these cells. Using a gut loop model we now demonstrate that covalently-membrane-bound UEA1 similarly targets polymerised liposomes (Orasomes, approximately 200 nm diameter), potential biocompatable oral vaccine delivery vehicles, to mouse M cells. Targeting was inhibited by alpha-L-fucose while the co-entrapped adjuvant, monophosphoryl Lipid A (MPL), failed to exert any detrimental effect on UEA1-mediated M cell targeting. Lectin-mediated M cell targeting may thus permit the efficacy of mucosal vaccines to be enhanced if cellular relationship between particle binding and immune outcome can be established.