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Studies of Brucella lipopolysaccharide
Developments in Biological Standardization
|January 1, 1976
Summary
Brucella endotoxin, unlike other gram-negative endotoxins, is found in the phenol phase. Acetone extraction does not remove lipid A, preserving endotoxic activity and complex dermal responses.
Area of Science:
- Microbiology
- Immunology
Background:
- Brucella endotoxin exhibits unique extraction properties compared to other Gram-negative endotoxins.
- Previous studies indicated altered endotoxic activity after acetone extraction.
Purpose of the Study:
- To investigate the effect of acetone extraction on Brucella endotoxin's lipid A component and endotoxic activity.
- To elucidate the components responsible for the dermal response to Brucella lipopolysaccharide (LPS).
Main Methods:
- Repeated the Redfearn hot phenol water extraction procedure on acetone-extracted Brucella cells.
- Assessed endotoxic activity in the phenol and aqueous phases.
- Evaluated dermal responses in sensitized guinea pigs.
Main Results:
- The majority of endotoxic activity remained in the phenol phase after acetone extraction.
- Acetone treatment did not remove lipid A, which is implicated in lethality and skin necrosis.
- Dermal reactions to Brucella LPS involved innate lipid A toxicity, antibody-mediated polysaccharide responses, and polypeptide-mediated delayed hypersensitivity.
Conclusions:
- Brucella endotoxin's unique partitioning in the phenol phase is confirmed, even after acetone extraction.
- Lipid A is not removed by acetone extraction and contributes to endotoxin's toxicity.
- The dermal response to Brucella LPS is multifactorial, involving lipid A, polysaccharide, and polypeptide components.