CHP 3: Complement System Flashcards
When does a complement become activated?
When a Protease cleaves them
What are the three different functions after the case of proteolytic cleavage reactions?
1) Opsonin tags
2) MAC
3) direct killing of pathogens through holes
What is the function of C3a?
induce inflammation and recruit and activate granulocytes
If a pathogen has syalic acid will the complement system be able to function properly?
No, syalic acid plays as an inhibitor
What are the three pathways of the complement system? How are they activated?
1) Alternative – reaction of thioester bond with water
2) Lectin – binding of a oliogosaccharide with mannose terminal ending
3) Classical – binding to immunoglobulin or C-reactive protein
What functions does C3a have?
Induce inflammatory responses and granulocyte activation
What functions does C3b have?
Acts are an opsonin and tags pathogens for easier immune recognition
Pathogen opsonization
Which of the pathways creates a soluble C3 convertase?
Alternative pathway
Alternative pathway can create two types of C3 convertase, where are these located?
1) a soluble C3 convertase
2) a alternative pathway C3 convertase that is bound the surface of a pathogen
How are C3 convertase deactivated in the alternative pathway?
1) DAF - decay accelerating factor
2) MCP - membrane cofactor protein
Which factor plays a role in stabilizing C3bBb (alternative C3 convertase)?
Factor P
What must occur in order for our system to form alternative C5 convertase?
Binding of two C3 convertase
What functions do C3 and C5 have? How do they cause inflammation?
1) Bind to endothelial cells to increase vascular permeability
2) act as chemoattractans for phagocytes
3) increase expression of complement receptors on phagocytes
3) induce degranulation of mast cells and basophils
The secretion of IL-6 cytokines from macrophages results in liver cell production acute phase proteins such as?
Mannose binding lectin and C-reactive protein which further enhance the innate immune response by amplifying the complement system
What response connects activation of innate immune cells to complement activation?
acute phase response
