title: Optimized procedures for the coupling of proteins to liposomes.
abstract: A general, optimized method for coupling proteins to liposomes is presented. This procedure utilizes streptavidin covalently coupled to liposomes to allow the subsequent attachment of a variety of biotinated proteins of interest. In the first part of this study, covalent methods for coupling proteins to liposomes which contain the lipid derivatives MPB-PE and PDP-PE were examined. The maleimide lipid derivative MPB-PE was found to allow more efficient coupling. Thin layer chromatography however revealed that during the standard synthesis of MPB-PE, an impurity was generated which can constitute 40% or more of the derivatized PE. An improved method for the synthesis and isolation of pure MPB-PE is presented here. Subsequently, optimized conditions for the covalent coupling of streptavidin to liposomes containing pure MPB-PE were determined. The flexibility of the streptavidin-liposome system for the preparation of various types of ligand bearing liposomes is demonstrated by the rapid association of a variety of biotinated proteins to streptavidin-liposome systems. The ability of these conjugates to target to specific cell populations in vitro as directed by defined biotinated monoclonal antibodies is demonstrated.
authors.affiliation: University of British Columbia, Faculty of Medicine, Department of Biochemistry, Vancouver, Canada.
authors.forename: H C
authors.initials: HC
authors.lastname: Loughrey
authors.forename: L S
authors.initials: LS
authors.lastname: Choi
authors.forename: P R
authors.initials: PR
authors.lastname: Cullis
authors.forename: M B
authors.initials: MB
authors.lastname: Bally
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D004337:Drug Carriers; D005434:Flow Cytometry; D006863:Hydrogen-Ion Concentration; D008081:Liposomes; D008301:Maleimides / Q000378:metabolism; D011506:Proteins; D019809:Streptavidin
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D004337:Drug Carriers; D008081:Liposomes; D008301:Maleimides; D011506:Proteins; C017071:biotin-binding proteins; C043592:maleimide; D019809:Streptavidin