Immunology Complement System
Complement refers to a system of some non-specific proteins present in normal human and animal serum, which are activated characteristically by antigen-antibody reactions and subsequently lead to a number of biologically significant consequences.
Complement System Components
There are 9 components of complement: C1, C2, C3, C4, C5, C6, C7, C8 and C9.
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Complement System Pathways
There are two pathways through which the complement system acts.
Complement System Effects Of Complement
1. Complement leads to bacteriolysis and cytolysis through membrane damage.
2. C3a and C5a cause degranulation of mast cells to release histamine.
- This leads to an inflammatory reaction.
Hypersensitivity Reaction
- Complement participates in type 2 and type 3 hypersensitivity reactions.
4. Endotoxic Shock.
- Excessive C3 activation and platelet adherence lead to endotoxic shock.
5. Immune Adherence.
- Complement bound to antigen-antibody complexes adheres to erythrocytes or to platelets.
- This is called immune adherence.
6. Opsonisation
- Complement helps in the destruction of pathogens through opsonization.
7. Autoimmune Diseases.
- Decreased levels of serum complement lead to autoimmune diseases.
