The C5b-9 complex: subunit composition of the classical and alternative pathway-generated complex
Journal of Immunology (Baltimore, Md. : 1950)
|May 1, 1976
Insights
The complement system's C5b-9 membrane attack complex has a consistent composition. Band V protein is a subunit of the soluble complex, likely representing a membrane site.
Area of Science:
- Immunology
- Molecular Biology
Background:
- The complement system is crucial for innate immunity.
- The membrane attack complex (MAC), C5b-9, is the terminal effector of complement.
- Understanding MAC composition is key to its function.
Purpose of the Study:
- To investigate the composition of the soluble membrane attack complex (C5b-9).
- To identify the role of Band V protein in the C5b-9 complex.
Main Methods:
- Biochemical analysis of the complement cascade.
- Isolation and characterization of soluble C5b-9 complexes.
Main Results:
- The composition of the C5b-9 complex is invariant across different complement activation pathways.
- Band V protein was identified as a consistent subunit of the soluble C5b-9 complex.
- Band V protein is not essential for complement-dependent cytolysis.
Conclusions:
- The final structure of the membrane attack complex (C5b-9) is conserved regardless of the activation pathway.
- Band V protein is a component of the soluble C5b-9 complex.
- Band V protein may serve as a membrane-bound equivalent to the nascent C5b-9 complex in serum.
Abstract:
The membrane attack complex of complement (C5b-9) is identical in composition regardless of which pathway of activation was instrumental in its formation. Band V protein was consistently a subunit of the soluble complex. Since band V protein is not required for complement-dependent cytolysis, it probably represents a membrane site equivalent in serum of the nascent C5b-9 complex.
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