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In vivo complement activation by polyanion--polycation complexes: evidence that C5a is generated intravascularly
Clinical Immunology and Immunopathology
|October 1, 1983
Summary
Polyanion-polycation complexes, like heparin-protamine, activate the complement system in vivo, causing granulocytopenia. This highlights a potential cause for adverse effects during clinical heparin neutralization.
Area of Science:
- Immunology
- Pharmacology
Background:
- In vitro studies show polyanion-polycation interactions activate the complement system.
- Heparin-protamine is a clinical model for polyanion-polycation interactions.
Purpose of the Study:
- To investigate in vivo complement activation by polyanion-polycation complexes.
- To determine the role of complement activation in adverse effects of heparin neutralization.
Main Methods:
- Utilized a rabbit model to study intravascular complement activation.
- Documented granulocytopenia and C5a generation.
- Administered cobra venom factor to deplete complement.
Main Results:
- Intravascular polyanion-polycation complexing caused rapid complement activation beyond early components.
- Generated biologically reactive products like C5a.
- Complement depletion abolished the observed effects.
Conclusions:
- Polyanion-polycation complexing triggers in vivo complement activation, leading to C5a generation.
- Complement system activation may cause adverse effects during clinical heparin neutralization.
- Suggests a role for non-immune inflammatory mediator generation via polyion interactions.