Related Experiment Videos
Activation of the classical complement pathway by nephritic factor bound to the alternative pathway C3/C5 convertase
Journal of Immunology (Baltimore, Md. : 1950)
|January 1, 1979
Summary
Nephritic Factor (NF), an autoantibody activating the alternative complement pathway, binds and activates C1, the first component of the classical pathway. This interaction is dependent on the amount of NF present on the cell surface.
Area of Science:
- Immunology
- Complement System Biology
Background:
- Nephritic Factor (NF) is an IgG autoantibody that activates the alternative complement pathway.
- NF is associated with certain types of nephritis and targets the C3 convertase (C3bB).
Purpose of the Study:
- To investigate if the NF-stabilized C3 convertase (EC3bBNF) on cell surfaces can bind and activate the classical complement pathway's first component, C1.
Main Methods:
- Studied the binding of C1q to EC3bBNF.
- Assessed the dependence of C1q binding and C1 activation on the number of NF molecules per cell.
- Monitored the proteolytic conversion of proenzyme C1s to activated C1s.
Main Results:
- EC3bBNF demonstrated binding to C1q.
- C1q binding and subsequent C1 activation were directly proportional to the number of NF molecules bound to the cell.
- C1 activation was confirmed by the conversion of C1s to C1s.
Conclusions:
- The NF-stabilized C3 convertase (EC3bBNF) effectively binds and activates C1, initiating the classical complement pathway.
- This finding suggests a potential link between alternative and classical complement pathway activation mediated by NF in nephritis.