Complement System Flashcards
Define complement system
The compliment system is part of the immune system that enhances the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism
Why is it named complement system
Because it was first identified as a heat liable component of serum that complemented antibodies in killing bacteria
Where are complement proteins synthesized
Liver
What other two cells/ tissues synthesize complement proteins
Macrophages and Fibroblast
What is complement made up of
Large number of distinct plasma proteins
How is the complement activated
- In a cascading manner
2. By microbes and antibodies that are attached to microbes and other antigens
Mention the 3 ways complement kills microbes
- Opsonization
- Inflammation
- Cytolysis
What does activation of complement involve
The sequential proteolysis of proteins to generate enzyme complexes with proteolytic activity
Biological active cleavage products of complement activation become covalently attached to
- Microbial cell surface
- Antibodies bound to microbes and other antigens
- Apoptotic bodies
What do by products of complement stimulate
Inflammatory reaction
What inhibits complement activation
Regulatory proteins that are present on normal host cells and absent from microbes
What’s the central event in complement activation
Proteolysis of the complement protein C3
List the importance of complement protein C3
- Generates biological active products
2. Covalent attachment of a product C3 called C3b to microbial surfaces or to antibody bound to antigen
List the regulatory proteins
C1- inhibitor Factor I C4bBP Factor H S protein Anaphylatoxins inactivator
List the pathways of complement system
Classical pathway(antigen-antibody complex) Lectin pathway Alternative pathway (pathogen surface)
