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Critical Reviews™ in Therapeutic Drug Carrier Systems
IF: 2.414 5-Year IF: 3.324 SJR: 0.573 SNIP: 0.551 CiteScore™: 2.43

ISSN Print: 0743-4863
ISSN Online: 2162-660X

Critical Reviews™ in Therapeutic Drug Carrier Systems

DOI: 10.1615/CritRevTherDrugCarrierSyst.v15.i1.20
32 pages

The Interaction of Liposomes with the Complement System

Janos Szebeni
Department of Membrane Biochemistry, Walter Reed Army Institute of Research, 503 Robert Grant Avenue Silver Spring, MD 20910-7580


Activation of complement (C) by haptenized liposomes has been utilized for a long time to study the interaction of biological membranes with C proteins, or as a sensitive immunoassay for the measurement of specific antigens, antibodies, or serum hemolytic C levels. However, it has been increasingly recognized that regardless of antigenicity, C activation is an intrinsic property of all charged phospholipid/cholesterol bilayers. Liposome-induced C activation and its biological consequences show significant interspecies and interindividual variation, and critically depend on the properties of vesicles as well. Activation can proceed through both the classical and the alternative pathways, with or without the involvement of antibodies. The practical significance of the phenomenon is twofold: 1) opsonization of the vesicles promotes their clearance from the circulation and 2) the liberation of C3a and C5a can cause numerous, potentially adverse, biological reactions. In fact, many cardiovascular and hematological changes observed following administration of liposomes in vivo can be explained by C activation; a fact that has not yet gained wide recognition in the field of drug-carrier liposomes.