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

Journal Article · Tue Sep 08 04:00:00 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), Journal Name: Biochemistry; (United States) Vol. 26:18; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

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