Defense against extracellular pathogens Flashcards
How many different isotopes of immunoglobulin are there
9
What are the two regions on immunoglobulin
Fab
Fc
Which region on immunoglobulin binds to the antigen
Which region points away from the antigen
Fab
Fc
Which isotopes trigger complement proteins
IgM
IgG
Which isotopes trigger phagocyte binding
IgG
IgA
Which isotopes trigger mast cell binding
IgE
What is the advantage of having different isotopes
Different types of defensive processes activated because of different antibodies
When are complement proteins active
Activated in presence of infeciton
What active complement proteins does C3 (inactive complement protein) make
C3a + C3b
Reaction to show inactive C3 and what it becomes
C3—-> C3a+ C3b
What enzyme activates C3 into active complement proteins
C3 convertase
Names of the 3 reactions that produce C3 convertase
- Classical pathway
- Mb Lectin pathway
- Alternative pathway
What happens in the classical pathway
1) Immunoglobulin (IgG) binds to antigen and the Fc region points away from it
2) Binding of C1q triggers activation of C1s and C1r which causes them to be split into fragments
3) Split into C4 and C2
4) C4 forms C4a and C4b, C2 forms C2a and C2b
5) C4b and C2a combine to form C4b2a
6) C4b2a is C3 convertase
What happens in the Mb lectin pathway
1) Manose binding lectin binds to manose residues in microbial carbs
2) Activation of MASP 1 & MASP2 (which are bits attached to the top of mans binding lectin0
3) MASP1 & MASP2 activate C4 and C2
4) C4 and C2 split into C4a, C4b, C2a, and C2b
5) C4b and C2a combine to form C4b2a which is C3 convertase
What is the Alternative pathway
1) C3b binds to microbial surfaces
2) Bb binds to it
3) P protein also binds to it
4) this all makes- C3bBbP (which is C3 convertase)