complement stuff and random immu2011 stuff

Question 1

C3 tickover

Answer 1

intact C3 contains an inaccessible thioester group
C3 is continuously cleaved to generate C3b which could expose previously hiddne reactive thioester bond.

Microbes could be bound to c3b and opsonised, or quickly hydrolysed. It is spontaneous

Question 2

Factor D

Answer 2

turns protein B to Bb

Question 3

What is C1 made of?

Answer 3

C1q and a tetramer composed of 2 C1r and two C1

it must bind to 2 or more Fc portions.

Question 4

C3 convertase

Answer 4

C4b2a

C2 cleaved by C1 molecules.

Question 5

masp

Answer 5

serine protease that helps form C3 converatse

Question 6

how is complement tightly regulated in mammalian cells to prevent complement attacking us

Answer 6

DAF
- a membrane protein that disrupts the binding of factor B to C3b or the binding of C4b2a to C3b. It is basically the bully that tells you not to play with C3b because it is not cool. So you can’t create C5 Convertase for late stage

MCP
serves as a cofactor for proteolysis of C3b

C1 inhibitor, prevents the assembly of C1 complex

ficolin stuff