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Published on: January 2, 2013
Complement induces a transient increase in membrane permeability in unlysed erythrocytes
J A Halperin1, A Nicholson-Weller, C Brugnara
1Department of Physiology and Biophysics, Harvard Medical School, Boston, Massachusetts 02115.
The Journal of Clinical Investigation
|August 1, 1988
Summary
Low concentrations of human serum transiently increase sheep erythrocyte membrane permeability, allowing ion and molecule uptake without lysis. The C5b-8 complex mediates this effect, highlighting a novel role in complement activation.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Antibody-sensitized sheep erythrocytes (EA) are model systems for studying complement activation.
- Complement activation can lead to cell lysis or other functional changes.
Purpose of the Study:
- To investigate the effects of low concentrations of human serum on EA membrane permeability.
- To identify the complement components involved in serum-induced membrane changes.
Main Methods:
- Exposure of EA to low concentrations of human serum.
- Measurement of ion fluxes (Na+, K+) and uptake of L-glucose.
- Utilizing sera deficient in terminal complement components (C8, C9).
Main Results:
- Low serum concentrations induced a transient increase in EA membrane permeability in non-lysed cells.
- This resulted in net Na+ uptake and K+ decrease, without altering total cation content.
- C8 was required for the permeability change, while C9 was not.
Conclusions:
- The C5b-8 complement complex mediates a transient increase in erythrocyte membrane permeability.
- This mechanism occurs in unlysed erythrocytes during complement activation.
- Suggests a role for C5b-8 beyond cell lysis in complement-mediated effects.
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