Monoclonal antibodies as probes of high-density lipoprotein structure: identification and localization of a lipid-dependent epitope

Journal Article · Tue Sep 08 00:00:00 EDT 1987 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00392a038· OSTI ID:5878322

Silberman, S R; Bernini, F; Sparrow, J T; Gotto, Jr, A M; Smith, L C

Eight stable murine monoclonal antibodies (mabs) were raised against human high-density lipoproteins (HDL). Three different antibody reactivities were demonstrated by immunoblotting. A group of five antibodies were specific for apolipoprotein A-I (apoA-I) and bound to similar or overlapping epitopes. The second type of reactivity, shown by mab-32, was specific for apoA-II. In the third group, two antibodies showed high reactivity with apoA-II and slight cross-reactivity with apoA-I. The properties of two antibodies, mab M-30 specific for apoA-I and mab M-32 specific for apoA-II, were characterized in detail as probes of HDL structure. The association of /sup 125/I-labeled HDL or synthetic complexes of apoA-I and phosphatidylcholine with mab M-30 was lipid dependent. Mab M-32 binding to apoA-II was independent of lipid. The lipid-dependent epitope bound by mab M-30 has been localized to an 18 amino acid synthetic apoA-I peptide. Moreover, studies with HDL/sub 2/, HDL/sub 3/, and immunoadsorbed HDL subfractions indicate that binding of mab M-30 to HDL is influenced by some component within the microenvironment of individual HDL particles. These lines of evidence suggest that the molar ratio of apoA-I to apoA-II is the critical determinant. Binding of mab M-32 to HDL increased the reactivity of HDL to mab M-30 in a dose-dependent manner, indicating an unusual form of cooperativity between two mabs that recognize different proteins in HDL. These monoclonal antibodies will be valuable in studies of the metabolic significance of protein-protein and lipid-protein interactions in HDL.

• Research Organization: Baylor College of Medicine, Houston, TX
• OSTI ID: 5878322
• Journal Information: Biochemistry; (United States), Vol. 26:18
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
APOLIPOPROTEINS
MOLECULAR STRUCTURE
RADIOIMMUNOASSAY
DOSE-RESPONSE RELATIONSHIPS
IODINE 125
MAN
MICE
MONOCLONAL ANTIBODIES
PHYSIOLOGY
ANIMALS
ANTIBODIES
BETA DECAY RADIOISOTOPES
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
IMMUNOASSAY
IMMUNOLOGY
INTERMEDIATE MASS NUCLEI
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ISOTOPE APPLICATIONS
ISOTOPES
LIPIDS
LIPOPROTEINS
MAMMALS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PRIMATES
PROTEINS
RADIOASSAY
RADIOIMMUNOLOGY
RADIOISOTOPES
RODENTS
TRACER TECHNIQUES
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550601* - Medicine- Unsealed Radionuclides in Diagnostics