Complement

Question 1

Complement Fxn
Host benefit:
Host detriment:

Answer 1

• opsonization to enhance phagocytosis
• phagocyte attraction and activation
• lysis of bacteria and infected cells
• regulation of antibody responses
• clearance of immune complexes
• clearance of apoptotic cells

Inflammation, anaphylaxis

Question 2

alteration of C proteins such that they interact with the next component

Answer 2

C-activation

Question 3

utilization of C by Ag-Ab complexes

Answer 3

C-fixation

Question 4

dilution of serum which lyses 50% of a standardized suspension of Ab-coated r.b.c

Answer 4

Hemolytic units (CH50)

Question 5

denaturation (usually by heat) of an early C-component resulting in loss of hemolytic activity

Answer 5

C-inactivation

Question 6

altered C-protein which acts as a proteolytic enzyme for another C-component

Answer 6

Convertase/esterase

Question 7

Activated component are usually over-lined

Answer 7

C1qrs

Question 8

When enzymatically cleaved, the _, binds to the activation complex or membrane and the smaller peptide is released in the microenvironment

Answer 8

larger moiety

Question 9

antibody

dependent

Answer 9

CLASSICAL

PATHWAY

Question 10

antibody

independent

Answer 10

LECTIN
PATHWAY

ALTERNATIVE
PATHWAY

Question 11

is C3 convertase

Answer 11

C4b2a

Question 12

is C5 convertase

Answer 12

C4b2a3b

Question 13

Prokinin; cleaved by plasmin to yield kinin, which results in edema

Answer 13

C2b

Question 14

Anaphylotoxin; can activate basophils and mast cells to degranulate resulting in increased vascular permeability and contraction of smooth muscle cells, which may lead to anaphylaxis

Answer 14

C3a

Question 15

Opsonin

Activation of phagocytic cells

Answer 15

C3b

Question 16

Anaphylaotoxin

Answer 16

C4a

Question 17

Opsonin

Answer 17

C4b

Question 18

C1-inhibitor (C1-INH); dissociates C1r and C1s from C1q

Answer 18

All

Question 19

C3a-inactivator (C3a-INA; Carboxypeptidase B)

Answer 19

C3a

Question 20

Factors H and I; Factor H facilitates the degradation of C3b by Factor I

Answer 20

C3b

Question 21

C3a-INH

Answer 21

C4a

Question 22

C4 binding protein (C4-BP) and Factor I; C4-BP facilitates degradation of C4b by Factor I; C4-BP also prevents the association of C2a with C4b thus blocking formation of C3 convertase

Answer 22

C4b

Question 23

prevents the binding of factor B to C3b

Answer 23

DAF

Question 24

dislodges C3b-bound factor Bb

Answer 24

DAF

Question 25

Generation of C5 convertase leads to the activation of the

Answer 25

Lytic pathway

Question 26

Biological Effects

C2b (prokinin)
C3a (anaphylatoxin)
C3b (opsonin)
C4a (anaphylatoxin)
C4b (opsonin)
C5a (chemotactic factor)

Answer 26

edema
--
mast cell degranulation
anaphylaxis
--
opsonization; phagocyte activation
--
as C3, but less potent
--
opsonization; phagocytosis

Question 27

Complement Deficiencies and Disease Classical Pathway

C1INH

C1, C2, C4

Answer 27

Hereditary
Angioedema

Predisposition
to SLE

Question 28

Complement Deficiencies and Disease Lectin Pathway

MBL

Answer 28

Susceptibility to bacterial infections in infants or

immunosuppressed

Question 29

Complement Deficiencies and DiseaseAlternative Pathway

Factors B or D

C3

C5, C6, C7 C8, or C9

Answer 29

Susceptibility to pyogenic (pus-forming) bacterial infections

Susceptibility to bacterial infections

Susceptibility to Gram-negative infections