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Optimized procedures for the coupling of proteins to liposomes

1990; Elsevier BV; Volume: 132; Issue: 1 Linguagem: Inglês

10.1016/0022-1759(90)90394-b

1872-7905

Helen Loughrey, Lewis S. L. Choi, Pieter R. Cullis, Marcel B. Bally,

Monoclonal and Polyclonal Antibodies Research

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.