Complement activation in human serum by liposome-encapsulated hemoglobin: the role of natural anti-phospholipid antibodies.
In exploring the occurrence and mechanism of liposome-encapsulated hemoglobin (LEH)-induced complement (C) activation, we found that normal human serum contained low titers of IgG and IgM class natural antibodies with reactivity against LEH, and that the amount of vesicle-bound IgM significantly correlated with LEH-induced C consumption. IgM binding to LEH was inhibited by phosphocholine and ATP, but not by choline chloride. These data suggest that naturally occurring antibodies play a key role in LEH-induced C activation, and that a major portion of these antibodies are directed against the phosphate moiety on the phospholipid headgroups of liposome bilayers.
Szebeni
J
J
Department of Membrane Biochemistry, Walter Reed Army Institute of Research, Washington, DC 20307-5100, USA.
Wassef
N M
NM
Rudolph
A S
AS
Alving
C R
CR
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000906:Antibodies / Q000097:blood / Q000494:pharmacology*; D001241:Aspirin / Q000031:analogs & derivatives / Q000378:metabolism; D002794:Choline / Q000494:pharmacology; D003167:Complement Activation / Q000187:drug effects* / Q000502:physiology; D003165:Complement System Proteins / Q000276:immunology / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000378:metabolism; D004339:Drug Compounding; D004797:Enzyme-Linked Immunosorbent Assay; D006454:Hemoglobins / Q000494:pharmacology*; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology / Q000378:metabolism; D007075:Immunoglobulin M / Q000276:immunology / Q000378:metabolism; D008081:Liposomes / Q000378:metabolism*; D010743:Phospholipids / Q000276:immunology / Q000378:metabolism; D010767:Phosphorylcholine / Q000494:pharmacology; D011485:Protein Binding
D000906:Antibodies; D003432:Cross-Linking Reagents; D006454:Hemoglobins; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D008081:Liposomes; D010743:Phospholipids; D010767:Phosphorylcholine; C030830:succinyldisalicylic acid; D000255:Adenosine Triphosphate; D003165:Complement System Proteins; D002794:Choline; D001241:Aspirin