Related Experiment Videos
Interaction of fibronectin with complement component C3
Insights
Human plasma fibronectin binds to complement component C3 fragments (C3c and C3d). This interaction suggests fibronectin may link C3-coated particles to other structures.
Area of Science:
- Immunology
- Biochemistry
Background:
- Complement component C3 activation generates C3a and C3b fragments.
- Further cleavage of C3b produces C3c and C3d fragments.
- Human plasma fibronectin is a key protein in the immune system.
Purpose of the Study:
- To investigate the interaction between human plasma fibronectin and complement component C3 fragments.
- To determine if fibronectin binds to native C3 and its cleavage products, C3c and C3d.
Main Methods:
- Enzyme immunoassay was used to study the binding.
- Interactions were tested with native C3 from human sera and isolated C3c and C3d fragments.
- Binding inhibition assays were performed.
Main Results:
- Human C3 from all tested sera bound to solid-phase fibronectin.
- Soluble and fluid-phase fibronectin bound to solid-phase C3c and C3d.
- Fibronectin binding to C3c and C3d was inhibited by fluid-phase C3c and C3d.
Conclusions:
- Human plasma fibronectin interacts with C3 fragments (C3c and C3d).
- These findings suggest a potential role for fibronectin in bridging C3-coated particles to other biological structures.
- This interaction may be significant in immune responses and particle clearance.
Abstract:
The activation of the complement component C3 generates C3a and C3b fragments, and the physiological cleavage of C3b further yields C3c and C3d fragments. We studied here by enzyme immunoassay the ability of human plasma fibronectin to interact with native C3 of human sera and with isolated C3c and C3d fragments of C3. C3 from sera of all six individuals tested bound to solid-phase fibronectin. Soluble fibronectin bound to solid-phase C3c and C3d, and fluid-phase C3c and C3d also bound to solid-phase fibronectin. The binding of fibronectin to solid-phase C3c and C3d could be inhibited by fluid-phase C3c and C3d. The results suggest the possibility that soluble fibronectin may attach to C3-coated particles or that C3-coated particles may adhere to fibronectin-containing structures.