Expression of human apolipoprotein A-I epitopes in high density lipoproteins and in serum

Journal Article · Wed Jul 01 04:00:00 EDT 1987 · J. Lipid Res.; (United States)

OSTI ID:6090231

Marcel, Y L; Jewer, D; Vezina, C; Milthorp, P; Weech, P K

The expression and immunoreactivity of apolipoprotein (apo) A-I epitopes in high density lipoproteins (HDL) and serum has been investigated using two series of monoclonal antibodies (Mabs) which have been described elsewhere. Series 1 Mabs, identified as 3D4, 6B8, and 5G6, were obtained by immunization and screening with apoA-I, and series 2 Mabs, identified as 2F1, 4H1, 3G10, 4F7, and 5F6, were obtained by immunization and screening with HDL. These Mabs were characterized with respect to their binding to HDL particles in solution. In series 2 Mabs, 2F1, 3G10, and 4F7, which react with apoA-I CNBr-fragments 1 and 2, could precipitate 100% of /sup 125/I-labeled HDL, while 4H1 and 5F6, which react with CNBr fragments 1 and 3, precipitated 90 and 60% of /sup 125/I-labeled HDL, respectively. Therefore, three distinct epitopes mapped to CNBr fragments 1 and 2 have been identified which are expressed on all HDL particles, indicating that several antigenic do mains exist on apoA-I which have the same conformation on all apoA-I-containing lipoproteins. The Mabs reacting at these sites have significantly higher affinity constants for /sup 125/I-labeled HDL than those that failed to precipitate 100% of HDL. This suggests that the high affinity Mabs react with apoA-I epitopes that are both expressed on all lipoproteins and located in thermo-dynamically stable regions of the molecules. All Mabs from series 1 precipitated 35% or less of /sup 125/I-labeled HDL prepared from freshly collected serum, but the proportion of HDL particles expressing the epitopes for these Mabs doubled or more upon serum storage at 4 degrees C. The time course of the alteration of apoA-I antigen in vitro was measured in three normolipemic donors.

• Research Organization: Clinical Research Institute of Montreal, Quebec
• OSTI ID: 6090231
• Journal Information: J. Lipid Res.; (United States), Journal Name: J. Lipid Res.; (United States) Vol. 28:7; ISSN JLPRA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
ANIMALS
ANTIBODIES
ANTIOXIDANTS
APOLIPOPROTEINS
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
CARBOXYLIC ACIDS
CHELATING AGENTS
DAYS LIVING RADIOISOTOPES
EDTA
ELECTRON CAPTURE RADIOISOTOPES
IMMUNE REACTIONS
IMMUNOASSAY
IMMUNOLOGY
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LIPIDS
LIPOPROTEINS
MAMMALS
MAN
MONOCLONAL ANTIBODIES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
PRIMATES
PROTEINS
RADIOASSAY
RADIOIMMUNOASSAY
RADIOIMMUNOLOGY
RADIOISOTOPES
REACTION KINETICS
TRACER TECHNIQUES
VERTEBRATES