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Distribution and kinetics of lipoprotein-bound endotoxin
J H Levels1, P R Abraham, A van den Ende
1Department of Vascular Medicine, Academic Medical Center, Amsterdam, The Netherlands. h.levels@amc.uva.nl
Infection and Immunity
|April 9, 2001
Summary
Lipopolysaccharide (LPS) binds to lipoproteins in human blood, with high-density lipoprotein (HDL) showing the highest capacity. This binding is specific and rapid, suggesting a key role for lipoproteins in detoxifying endotoxins.
Area of Science:
- Biochemistry
- Immunology
- Microbiology
Background:
- Lipopolysaccharide (LPS) is a potent endotoxin from gram-negative bacteria.
- LPS is often found associated with plasma lipoproteins.
- Lipoprotein sequestration of LPS may be a detoxification mechanism.
Purpose of the Study:
- To analyze LPS distribution, binding capacity, and kinetics with lipoproteins in human blood.
- To investigate LPS binding while preserving lipoprotein integrity.
- To compare binding across different LPS chemotypes.
Main Methods:
- Used high-performance gel permeation chromatography.
- Employed fluorescently labeled LPS of three chemotypes (O111:B4, J5, Re595).
- Analyzed LPS binding in human whole blood and plasma.
Main Results:
- LPS predominantly binds to high-density lipoprotein (HDL) (60%), followed by low-density lipoprotein (LDL) (25%) and very-low-density lipoprotein (VLDL) (12%).
- Lipoprotein saturation capacity for LPS exceeds 200 microg/ml, surpassing clinical concentrations.
- Binding kinetics are chemotype-dependent, with rapid initial association and subsequent redistribution.
Conclusions:
- Lipoprotein binding of LPS is highly specific under physiological conditions.
- HDL exhibits the highest binding capacity for LPS.
- Lipoprotein saturation capacity for endotoxin is substantial, and binding kinetics vary by LPS chemotype.