Key Points
- To isolate and characterize a specific subpopulation of human low-density lipoprotein particles containing both apolipoprotein B and apolipoprotein E using an anti-apolipoprotein B monoclonal antibody.
- Purified low-density lipoprotein particles from normolipidemic human plasma using single-step immunoaffinity chromatography with a monoclonal antibody against apolipoprotein B.
- Characterized particle size, flotation coefficient, electrophoretic mobility, apolipoprotein ratio, and lipid composition.
- Assayed receptor-mediated binding kinetics of the isolated particles using cultured human hepatoma HepG2 cell membranes.
- Isolated homogeneous LP-B:EL2 particles measuring 20 nm with a flotation coefficient of Sf = 9.5, an apolipoprotein B to E molar ratio near 2:1, and a lipid composition of 47.3% cholesterol, 48.0% phospholipids, and 4.7% triglycerides.
- LP-B:EL2 particles accounted for less than 10% of total plasma apolipoprotein B in most normolipidemic individuals.
- LP-B:EL2 exhibited specific, saturable receptor binding to HepG2 cell membranes that was significantly greater than that of low-density lipoproteins containing apolipoprotein B alone.
Structured PICO
PPopulationNormolipidemic human plasma and human hepatoma HepG2 cells
IInterventionIsolation of LP-B:EL2 particles using a monoclonal antibody to human plasma apolipoprotein B in a single-step immunoaffinity chromatography procedure
CComparatorLow-density lipoprotein particles containing only apolipoprotein B
OOutcomeBinding to the membranes of human hepatoma HepG2 cellssurrogate
A specific subpopulation of LDL particles containing both apo B and apo E (LP-B:EL2) demonstrates significantly higher receptor-mediated binding to hepatic cells compared to LDL containing only apo B.