Complement System

Question 1

Complement system is defense against

Answer 1

mainly bacteria

Question 2

proteins for CS are synthesized in

Answer 2

the liver

Question 3

many CS proteins are present as

Answer 3

inactive form in blood and other fluids and require activation for effect

Question 4

activation pathways

Answer 4

classical(CP), Alternative(AP) and Terminal(TP)

Question 5

a deficiency in the terminal pathway components leads to

Answer 5

susceptibility to Neisseria Sp infections

Question 6

Membrane attack complex (MAC)=

Answer 6

in terminal/common C5b, C6, C7, C8, C9

Question 7

activation of classical pathway leads to

Answer 7

convergence with terminal pathway

Question 8

Activation of classical pathway starts with

Answer 8

IgG(2 Fc’s needed) or IgM(only 1 needed) complex binds to C1

Question 9

Pentameric IgM=

Answer 9

5Fc-mu’s available to bind

Question 10

C1 cleaves

Answer 10

C4 to C4a and C4b and C2 to C2a and C2b

Question 11

C1 Cleavage forms

Answer 11

C4b2a= C3 convertase(CP)

Question 12

C3 convertase cleaves

Answer 12

C3 to C3a and C3b and forms C4b2a3b (C5 convertase)

Question 13

C5 convertase cleaves

Answer 13

C5a and C5b

Question 14

C5b binding to

Answer 14

the microbe surface initiations formation of MAC of the Terminal pathway

Question 15

Alternative pathway is activated by

Answer 15

spontaneously generated C3b deposits on activating surface

Question 16

Factor B binds to

Answer 16

C3b

Question 17

Factor B is cleaved by

Answer 17

Factor D and forms teh C3bBb

Question 18

C3bBbis also called

Answer 18

C3 convertase

Question 19

Poperdin extends

Answer 19

the half life of C3bBb by 6-10 fold

Question 20

C3bBb cleaves

Answer 20

C3 to C3a and C3b and forms C3bBb3b (C5 convertase)

Question 21

C3bBb3b cleaves

Answer 21

C5 to C5a and C5b

Question 22

classical proteins

Answer 22

C1,2,3,4,5

Question 23

Terminal proteins

Answer 23

C5b, 6,7,8,9

Question 24

Alternative proteins

Answer 24

C3b,3,5 Factor B, D Properdin

Question 25

role of C3b

Answer 25

opsonin mediated phagocytosis and elimination of immune complexes

Question 26

role of C3a, 4a, 5a

Answer 26

degranulation of mast cells and basophils

Question 27

Role of C5a

Answer 27

chemotaxis of neutrophils

Question 28

role of MAC

Answer 28

Osmotic lysis of bacteria

Question 29

role of regulatory complement proteins

Answer 29

protect autologous cells from complement mediated damage

Question 30

C1 INH, C1 esterase inhibitor binds

Answer 30

C1 to prevent spontaneous activation

Question 31

C4bp(binding protein binds

Answer 31

the fluid phase of C4b preventing attachment to cells and formation of C3 convertase

Question 32

Factor H binds

Answer 32

to C3b in fluid phase preventing the binding to the microbe

Question 33

Factor H competitively binds

Answer 33

C3b which leads to dissociation of C3bBb if it has formed.

Question 34

Decay accelerating Factor (DAF)

Answer 34

binds to membrane bound C3b or C4b blocking formation of C3 convertase or dissociating C3 convertases that formed.

Question 35

Anaphylatoxin inhibitor binds

Answer 35

C3a, C4a and C5a and inhibits binding to Cr3a/4a. C45a

Question 36

Factor I cleaves

Answer 36

C4b and C3b to inactive forms in presence of cofactors

Question 37

S- protein, CD59, and Homolgous restriction factor (HRF

Answer 37

inihibit formation of MAC on autologous cells.

Question 38

CR1

Answer 38

receptor on phagocytes and RBC that binds to C3b or C4b and is part of the opsonin/immune complex elimination

Question 39

CR2

Answer 39

receptor on B cells that binds C3bi- is a mode of epstein barr virus infection

Question 40

C3a/4a binds

Answer 40

C3a and C4a and is found on mast cells and basophils, it leads to degranulation and histamine release (CR5a binds C5a on mast cells and basophils for the same effect

Question 41

CR5a on neutrophils binds

Answer 41

C5a which is used as a chemotaxis for neutrophils

Question 42

Ch50 complement test

Answer 42

measures overall complement activity and whether or not it is low for c3 and c4

Question 43

Tissue damage activates

Answer 43

the intrinsic coagulation system and activates factor XII

Question 44

factor XII(a) activates

Answer 44

zymogen prekallikrein to kallikrein

Question 45

role of kallikrein

Answer 45

- -cleave kininogen to kininogena and brady kinin | - -cleaves C5 to C5a and C5b because C5a is chemotactic for neutrophils

Question 46

bradykinin increases

Answer 46

vascular permeability which is critical in inflammation

Question 47

Killikrein is inactivated by

Answer 47

C1INH