Complement 2 Flashcards
Why is the sea urchin one of our earliest ancestors?
One of the first animals to have a separate mouth and anus?
Which complement pathway isnt vital to have?
Lectin pathway
What does c1 cleave in the classical pathway?
C2 and C4
What happens once C2 and C4 are cleaved?
C2a and C4b form the c3 convertase enzyme
What two things can C3b do?
Bind to the surface of the pathogen, or become part of the enzyme
What can be done by the complex that involved c3 convertase and C3b?
It can cleave C5
What happens once C5b is on the surface of the microbe?
There is a cascade that leads to pore formation, and death of the microbe
Which complement component is the one that forms the pore?
C9
What needs to be bound onto the surface in order to activate the classical pathway?
Antibodies
What happens to C1 as a result of binding to an antibody?
C1 is activated
Generally, what is the smaller peptide?
The anaphylatoxin
Generally, what is the larger peptide?
The opsonin
What do anaphylatoxins do to the blood system?
Increase vascular permeability
Examples of anaphylatoxins?
C3a, C4a, C5a
What is a major source of complement components?
The liver
Why is it useful that many tissues can produce complement?
Local infection can be responded to with local complement activation
Why do anaphylatoxins increase vascular permeability?
So they can enter the blood and recruit immune cells
So the immune cells can then leave the vascular system and enter other tissues
Which pathway is C1 important in?
Classical pathway
What can C1 bind to?
IgG, IgM, CRP
What condition does C1 need to bind to IgG?
There needs to be two IgGs on the surface of the microbe
How many IgG binding domains does C1 have?
6
Makeup of C1?
Part that has the 6 IgG binding heads
Two serine proteases
What are the serine proteases in C1 used for?
Cleavage of C2 and C4
What does MBL-MASP look similar to?
C1
What do both C1 and MBP-MASP do?
Activate C2 and C4
What can C4a and C4b do once they have formed a complex?
Cleave C3
What is the central complement component?
C3
Concentration of C3 in blood?
1mg/ml
What is the most abundant molecule in the blood?
C3
