Novel anti-cholesterol monoclonal immunoglobulin G antibodies as probes and potential modulators of membrane raft-dependent immune functions.
Natural autoantibodies against cholesterol are present in the sera of all healthy individuals; their function, production, and regulation, however, are still unclear. Here, we managed to produce two monoclonal anti-cholesterol antibodies (ACHAs) by immunizing mice with cholesterol-rich liposomes. The new ACHAs were specific to cholesterol and to some structurally closely related 3beta-hydroxyl sterols, and they reacted with human lipoproteins VLDL, LDL, and HDL. They bound, usually with low avidity, to live human or murine lymphocyte and monocyte-macrophage cell lines, which was enhanced substantially by a moderate papain digestion of the cell surface, removing some protruding extracellular protein domains. Cell-bound ACHAs strongly colocalized with markers of cholesterol-rich lipid rafts and caveolae at the cell surface and intracellularly with markers of the endoplasmic reticulum and Golgi complex. These data suggest that these IgG ACHAs may serve as probes of clustered cholesterol (e.g., different lipid rafts) in live cells and thus may also have immunomodulatory potential.
Bíró
Adrienn
A
Third Department of Internal Medicine, Research Laboratory, Semmelweis University, Budapest, Hungary.
Cervenak
László
L
Balogh
Andrea
A
Lorincz
András
A
Uray
Katalin
K
Horváth
Anna
A
Romics
László
L
Matkó
János
J
Füst
George
G
László
Glória
G
D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D000924:Anticholesteremic Agents / Q000494:pharmacology*; D002784:Cholesterol; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D006801:Humans; D007074:Immunoglobulin G / Q000494:pharmacology*; D019169:Jurkat Cells; D007700:Kinetics; D008075:Lipoproteins, HDL / Q000097:blood / Q000276:immunology; D008077:Lipoproteins, LDL / Q000097:blood / Q000276:immunology; D008079:Lipoproteins, VLDL / Q000097:blood / Q000276:immunology; D008081:Liposomes; D008563:Membrane Lipids / Q000378:metabolism; D021962:Membrane Microdomains / Q000187:drug effects / Q000276:immunology*; D018613:Microscopy, Confocal
D000911:Antibodies, Monoclonal; D000924:Anticholesteremic Agents; D007074:Immunoglobulin G; D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D008079:Lipoproteins, VLDL; D008081:Liposomes; D008563:Membrane Lipids; D002784:Cholesterol