Complement System

Question 1

Activates classical pathway

Answer 1

IgG, IgM

IgM being the most potent one,
IgG in decreasing order: 3,1,2

Question 2

Activates alternative pathway

Answer 2

Microbe surface molecules

Also IgA

Question 3

Lectin pathway is activated by

Answer 3

Mannose or other sugars on microbe surface

Question 4

Funtions as Anaphylactoid

Answer 4

C4a, C5a, C3a

Question 5

Functions as opsonin

Answer 5

C3b, inactive C3

Question 6

Deficiency of this complement component will result in hereditary angioneurotic edema

Answer 6

C1 esterase inhibitor

Question 7

Deficiency of this complement component is linked to recurrent neisserial infections

Answer 7

C5-C8

Question 8

Deficiency of this complement component has no known associated dse

Answer 8

C9

C-NINE (C-NONE)

Question 9

Most common complement deficiency

Answer 9

C2

Question 10

Most severe complement deficiency and associated to severe recurrent infections and glomerulonephritis

Answer 10

C3

Question 11

Deficiency of these complement components are associated to PNH

Answer 11

CD59/ MIRL

CD55/ DAF

Question 12

Dissociates C1r and C1s from C1q

Answer 12

C1 inhibitor

Question 13

Increases the dissociation of c3 convertase

Answer 13

DAF

Question 14

Inhibits MAC formation

Answer 14

MIRL/CD 59

MIRL: membrane inhibitor of reactive lysis

Question 15

Prevents attachment of C5bC6C7 to cell membrane

Answer 15

Vitronectin

Question 16

Activates C1s

Answer 16

C1r

Question 17

Binds to Fc of IgM or IgG

Answer 17

C1q

Question 18

Cleaves C4 and C2

Answer 18

C1s

Question 19

Starts pore formation

Answer 19

C8

Question 20

Initiates MAC

Answer 20

C5

Question 21

KEY INTERMEDIATE, INVOLVED IN ALL PATHWAY

Answer 21

C3

Most severe complement deficiency

Question 22

Stabilizes C3 convertase in the Alternative pathway

Answer 22

Properdin

Question 23

Cleaves factor B in alternative pathway

Answer 23

Factor D

Question 24

C3 convertase in the Classical pathway

Answer 24

C4b2a

Question 25

C3 convertase in alternative pathway

Answer 25

C3bBb P P: properdin, stabilizes C3 convertase of the alternative pathway

Question 26

C5 convertase of alternative pathway

Answer 26

C3bBbP3b

Question 27

C5 convertase of Classical pathway

Answer 27

C4b2a3b Also of the mannose pathway

Question 28

Helps cleave C4and C2 in the Lectin pathway

Answer 28

MASP-1

Question 29

CLEAVES C4 and C2 IN LECTIN PATHWAY

Answer 29

MASP-2

Question 30

Recognition unit

Answer 30

C1

Question 31

Activation unit

Answer 31

C4, C2, C3

Question 32

Membrane attack complex

Answer 32

C5-C9

Question 33

CRITICAL STEP IN THE FUNCTIONING OF THE COMPLEMENT SYSTEM

Answer 33

Activation of C3

Question 34

Deficiency of this inhibitor causes excessive complement activation and form the basis of development of hereditary angioneurotic edeme

Answer 34

C1 esterase inhibitor C1 esterase inhibitor blocks the binding of C1 to immune complex