Targeted delivery using immunoliposomes with a lipid-modified antibody-binding protein.

A recombinant antibody-binding protein originating from streptococcal protein G was modified with lipid in a site-directed manner by genetic engineering. The resulting lipoprotein was incorporated into the surface of liposomes by simple mixing. Immunoliposomes were then prepared by binding anti-IgG antibodies molecules onto the surface of proteoliposome via the lipid-anchored streptococcal protein G. Either small fluorophores or fluorescently labeled proteins were encapsulated into prepared immunoliposomes, and these molecular tracers could be delivered into cells whose surfaces were marked with specific antibodies.