Biomaterial Database

The interaction of liposomes with the complement system. 1998

J Szebeni

Department of Membrane Biochemistry, Walter Reed Army Institute of Research, Washington, D.C. 20307-5100, USA.

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.

UI	MeSH Term	Description	Entries
D008081	Liposomes	Artificial, single or multilaminar vesicles (made from lecithins or other lipids) that are used for the delivery of a variety of biological molecules or molecular complexes to cells, for example, drug delivery and gene transfer. They are also used to study membranes and membrane proteins.	Niosomes,Transferosomes,Ultradeformable Liposomes,Liposomes, Ultra-deformable,Liposome,Liposome, Ultra-deformable,Liposome, Ultradeformable,Liposomes, Ultra deformable,Liposomes, Ultradeformable,Niosome,Transferosome,Ultra-deformable Liposome,Ultra-deformable Liposomes,Ultradeformable Liposome
D001798	Blood Proteins	Proteins that are present in blood serum, including SERUM ALBUMIN; BLOOD COAGULATION FACTORS; and many other types of proteins.	Blood Protein,Plasma Protein,Plasma Proteins,Serum Protein,Serum Proteins,Protein, Blood,Protein, Plasma,Protein, Serum,Proteins, Blood,Proteins, Plasma,Proteins, Serum
D003167	Complement Activation	The sequential activation of serum COMPLEMENT PROTEINS to create the COMPLEMENT MEMBRANE ATTACK COMPLEX. Factors initiating complement activation include ANTIGEN-ANTIBODY COMPLEXES, microbial ANTIGENS, or cell surface POLYSACCHARIDES.	Activation, Complement,Activations, Complement,Complement Activations
D003169	Complement Inactivator Proteins	Serum proteins that negatively regulate the cascade process of COMPLEMENT ACTIVATION. Uncontrolled complement activation and resulting cell lysis is potentially dangerous for the host. The complement system is tightly regulated by inactivators that accelerate the decay of intermediates and certain cell surface receptors.	Complement Cytolysis Inhibiting Proteins,Complement Cytolysis Inhibitor Proteins,Complement Inactivating Proteins,Serum Complement Inactivators,Complement Inactivators, Serum,Inactivating Proteins, Complement,Inactivator Proteins, Complement,Inactivators, Serum Complement,Proteins, Complement Inactivating,Proteins, Complement Inactivator
D004337	Drug Carriers	Forms to which substances are incorporated to improve the delivery and the effectiveness of drugs. Drug carriers are used in drug-delivery systems such as the controlled-release technology to prolong in vivo drug actions, decrease drug metabolism, and reduce drug toxicity. Carriers are also used in designs to increase the effectiveness of drug delivery to the target sites of pharmacological actions. Liposomes, albumin microspheres, soluble synthetic polymers, DNA complexes, protein-drug conjugates, and carrier erythrocytes among others have been employed as biodegradable drug carriers.	Drug Carrier
D004342	Drug Hypersensitivity	Immunologically mediated adverse reactions to medicinal substances used legally or illegally.	Allergy, Drug,Hypersensitivity, Drug,Drug Allergy,Allergies, Drug,Drug Allergies,Drug Hypersensitivities,Hypersensitivities, Drug
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D000906	Antibodies	Immunoglobulin molecules having a specific amino acid sequence by virtue of which they interact only with the ANTIGEN (or a very similar shape) that induced their synthesis in cells of the lymphoid series (especially PLASMA CELLS).
D015926	Complement C3a	The smaller fragment generated from the cleavage of complement C3 by C3 CONVERTASE. C3a, a 77-amino acid peptide, is a mediator of local inflammatory process. It induces smooth MUSCLE CONTRACTION, and HISTAMINE RELEASE from MAST CELLS and LEUKOCYTES. C3a is considered an anaphylatoxin along with COMPLEMENT C4A; COMPLEMENT C5A; and COMPLEMENT C5A, DES-ARGININE.	C3a Complement,Complement 3a,Complement Component 3a,C3a, Complement,Complement, C3a,Component 3a, Complement