6- Complement System Flashcards
1
Q
What molecules are necessary for the initiation of the classical pathway of the complement system?
A
Antibody and C1q
2
Q
What molecules are necessary for the initiation of the lectin pathway of the complement system?
A
MBL
Manose-binding lectin
3
Q
What molecules are necessary for the initiation of the alternative pathway of the complement system?
A
P and D
4
Q
Describe the classical pathway of complement system
A
- start with antibody and C1q
- C1rs binds, then C4 binds
- C2 binds to C4
- C2 causes C3b to opsonize the pathogen and mark it for destruction
- then barrel formation of proteins around the pathogen and punches holes in pathogen
5
Q
Describe the lectin pathway of the complement system
A
- Starting with MBL, MASP-2 binds and is initiated
- the rest of the pathway is the same as classical
6
Q
Which of the three complement pathways is in adaptive immunity?
A
Classical pathway
7
Q
Describe the classical pathway of the complement system
A
- initiated when a complement fixing antibody (IgM, IgG) binds the antigen
- Binding site for the complement protein on Fc portion of the antibody ‘opens up’ when the antibody is bound to antigen
8
Q
Describe some of the components of the MB-Lectin Pathway
A
- initiated by the soluble pattern recognition molecules (PRR) that bind to carbohydrates on the microbe surfaces
- this activates enzymes that activate the complement
- part of innate immunity, adaptive is not required to initiate this pathway
9
Q
Which immunoglobulin is more efficient at activating the classical pathway of complement compared to IgG?
A
IgM
10
Q
A
