Chap 5

Question 1

What regulates complement function by directly inhibiting formation of the MAC?

Answer 1

Protectin (CD59)

Question 2

Protectin (CD59) regulates complement function by directly inhibiting formation of the?

Answer 2

MAC

Question 3

What is TRUE about the binding of C5b to the pathogen surface?

Answer 3

C5b both requires C6 binding to stabilize it before it dissociates away.
C6 and C7, is capable of forming the MAC on any cell membrane, pathogen, or host.

Question 4

Requires C6 binding to stabilize it before it dissociates and, when complexed to C6 and C7, is capable of forming the MAC on any cell membrane, pathogen, or host. These are characteristics of?

Answer 4

Binding of C5b to the pathogen surface

Question 5

First complement factor to be activated, resulting in insertion of one of its subunits into the pathogen surface in two of the three complement fixation pathways?

Answer 5

C4

Question 6

Provides serine protease activity in the classical complement activation pathway?

Answer 6

Both C1r and C1s act in the classical pathway.

Question 7

C1r and C1s provides what in the classical complement activation pathway?

Answer 7

serine

Question 8

Which form of IgM is MOST readily recognized by C1q?

Answer 8

“Staple-form” pentameric IgM

Question 9

The MAC consists of a multimeric complex of which of the following proteins that, by their association, forms a pore in the surface of the attacked cell?

Answer 9

C9

Question 10

On a holistic scale, the complement system plays a role in?

Answer 10

both specific and nonspecific pathogen defenses

Question 11

Acts as a protease that is required to generate the alternative pathway C3 convertase?

Answer 11

Factor D

Question 12

Capable of initiating the alternative pathway of complement fixation by directly binding to the surfaces of certain cell types?

Answer 12

Properdin

Question 13

Which of the following facilitates dissociation of both the C4b2a and C3bBb C3 convertases?

Answer 13

DAF (CD55)

Question 14

What immunoglobulin isotypes is the MOST efficient at initiating a complement fixation cascade?

Answer 14

IgM

Question 15

MBL MOST structurally similar to?

Answer 15

C1q

Question 16

BEST explain the timing of the classical pathway of complement fixation, relative to the other pathways of complement fixation, against a pathogen in an individual who has never been exposed to said pathogen?

Answer 16

No target for C1qrs exists on the surface of the pathogen in the earliest stages of the response to it.

Question 17

Which of the following acts as a serine protease that, with cofactors, cleaves C3b and C4b?

Answer 17

Factor I

Question 18

Complement components can be classified into seven functional categories, including?

Answer 18

Regulatory complement components.
Inflammatory mediators.
Enzymatic mediators.
Membrane attack proteins

Question 19

When activated, what utilizes its “a” component instead of the “b” component in the formation of the C3 convertase?

Answer 19

C2

Question 20

Addition of which of the following components to any C3 convertase leads to the formation of the C5 convertase?

Answer 20

C3b

Question 21

Based on your knowledge of complement activation pathways, predict which group of pathogens would be MOST susceptible to lysis by MACs.

Answer 21

Gram-negative pathogens and enveloped viruses are equally susceptible.

Question 22

Binds to surface-bound C3b during formation of the alternative C3 convertase?

Answer 22

Factor B

Question 23

Act as a bridge to connect complement labeled pathogens to effector immune cells?

Answer 23

Both C1R and C3aR are correct.

Question 24

When activated itself, acts as a protease that converts soluble C3 into C3a and C3b in the alternative pathway?

Answer 24

Factor B

Question 25

Complement fixation pathways can be initiated by a soluble C3 convertase?

Answer 25

Alternative

Question 26

MOST potent anaphylatoxin produced during the complement cascade?

Answer 26

C5a

Question 27

Directly activated as a soluble protein in the microenvironment surrounding a pathogenic cell?

Answer 27

C3

Question 28

How does binding of complement-opsonized microbes to CR1 facilitate clearing of the microbe from the host?

Answer 28

Promotion of phagocytosis of opsonized microbes by leukocytes.
Mediating phagocytosis of C3b-opsonized pathogen by B cells.
Secretion of proinflammatory cytokines.

Question 29

Of the molecules listed, which can be considered the key molecule in complement pathways?

Answer 29

C5 convertase

Question 30

Which of the following acts as a positive regulator of complement fixation via stabilization of C3bBb?

Answer 30

Properdin