Chapter 9.2 quiz Flashcards Preview

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Flashcards in Chapter 9.2 quiz Deck (48):
1

Which of the following is not a function of antibodies?

a. They neutralize pathogens by masking their surface

b. They act as molecular adaptors that bridge together pathogen and phagocyte surfaces

c. They exert toxic effects directly

d. They act as opsonins that mediate phagocytosis

e. They activate complement fixation

d. They act as opsonins that mediate phagocytosis

2

To mount the most effective antibody response that results in the synthesis of high-affinity antibodies, which of the following must occur?

a. recognition of thymus-independent (TI) antigens

b. isotype switching and affinity aturation

c. increased expression of TLR9 by B cells

d. somatic recombination

e. decreased expression of CD40 by B cells

b. isotype switching and affinity maturation

3

Immunoreceptor tyrosine-based activation motifs (ITAMs) are located on ____.

a the cytoplasmic tails of IgM

b. tyrosine kinases Blk, Fyn, nd Lyn

c. the cytoplasmic tails of Igalpha and Igbeta

d. breakdown products of C3b deposited on pathogen surfaces

e. thymus-independent antigens

c. the cytoplasmic tails of Igalpha and Igbeta

4

Identify the mismatched association.

a. Syk: Igbeta cytoplasmic tails

b. tyrosine kinase Lyn: CD81

c. B-cell co-receptor: CD21/CD19/CD81

d. C3b fragments: C3d and iC3b

e. hyper-IgM syndrome:CD40 ligand deficiency

b. tyrosine kinase Lyn: CD81

5

A primary focus of clonal expansion is best described as ____.

a. the location in the B-cell zone where conjugate pairs of B and T cells undergo cellular proliferation, isotype switching, and somatic hypermutation

b. the location in the medullary cords where conjugate pairs of B cells and T cells undergo cellular proliferation and IgM is secreted

c. the dark zone of the germinal center where centroblasts divide and pack closely together.

d. the initial wave of B-cell proliferation induced by T-independent antigens

b. the location in the medullary cords where conjugate pairs of B cells and T cells undergo cellular proliferation and Igm is secreted

6

A primary focus forms after a circulating naive B cells forms a conjugate pair with ___ in the ___ of the lymph node.

a. TH1 cell; B-cell zone

b. cytotoxic T cell; T-cell zone

c. follicular dendritic cell; germinal center

d. TFH; medullary cords

e. CD40 ligand; T-cell zone

d. TFH; medullary cords

7

B cells migrating directly from a primary focus to the medullary cords in a lymph node after activation with a T-dependent antigen differentiate into plasma cells that secrete predominantly ___.

a. IgD

b. IgE

c. sIgA

d. IgG

e. IgM

e. IgM

8

Lymphoblasts upregulate a transcription factor called ___ when they terminally differentiate into plasma cells.

a. NFkappa B

b. Bcl-xL

c. B-lymphocyte induced maturation protein 1 (BLIMP-1)

d. CD40

e. ICAM-1

c. B-lymphocyte induced maturation protein-1 (BLIMP-1)

9

The primary focus on B-cell expansion forms in the ___, whereas a secondary focus of B-cell expansion creates the ___.

a. T-cell area; medullary cords

b. medullary cords; T-cell area

c. T-cell area; B-cell area

d. medullary cords; germinal center

e. light zone; dark zone

d. medullary cords; germinal center

10

Proliferating centroblasts use the DNA-modifying enzyme activation-induced cytidine deaminase for ____.

a. cell proliferation

b. somatic hypermutation and isotype switching

c. apoptosis

d. upregulation of CD40

e. somatic recombination

b. somatic hypermutation and isotype switching

11

The main function of Bcl-xL is to ___ in the centrocyte.

a. provide death signals

b. induce somatic hypermutation

c. upregulate the expression of activation-induced cytidine deaminase

d. prevent apoptosis

e. induce isotype switching

d. prevent apoptosis

12

Engulfment of apoptotic centrocytes is facilitated by ___ in germinal centers.

a. follicular dendritic cells

b. immune-complex coated bodies (icosomes)

c. tingible body macrophages

d. antigen-specific B cells

e. antigen-specific TFH cells

c. tingible body macrophages

13

Which of the following is an accurate description of how centroblasts differ from centrocytes?

a. Centroblasts cease their expression of cell-surface immunoglobulins

b. Centroblasts divide more slowly than centrocytes

c. Centroblasts express CD44 but centrocytes do not

d. Centrocytes but not centroblasts initiate the process of isotype switching

e. Centroblasts participate in affinity matruation

a. Centroblasts cease their expression of cell-surface immunoglobulins

14

If a centrocyte does not interact with antigen and engage CD40 shortly after its derivation, then ___.

a. it recommences somatic hypermutation

b. it undergoes apoptosis

c. it moves back into the dark zone of the germinal center and switches its isotype

d. its surface immunoglobulin levels decreased and proliferation recommences

b. it undergoes apoptosis

15

____ is a mechanism that drives the preferential selection of immunoglobulins with the highest affinity for antigen.

a. Anergy

b. Isotype-switching

c. Affinity maturation

d. Antibody-dependent cell-mediated cytotoxicity

e. Transcytosis

c. Affinity maturation

16

___ in the switch regions positioned 5? to each heavy-chain C gene is induced by ___.

a. Somatic hypermutation; TI antigens

b. Chromatin remodeling; B-cell co-receptor signaling

c. recombination; survival signals received from follicular dendritic cells

d. Transcription; helper T-cell cytokines

e. Gene repression; apoptotic signals received from tingible body mactrophages

d. Transcription; helper T-cell cytokines

17

Plasma cells and memory B cells differentiate most immediately from ___.

a. centrocytes

b. centroblasts

c. B-1 cells

d. IgG-secreting B cells

e. Pre-B-cells

a. centrocytes

18

Which of the following statements is true regarding the complement component C4B?

a. Deficiency of C4B is associated with systemic lupus

b. C4B has similar properties to those of C4A

c. The thioester bond of C4B is preferentially acted upon by amino groups of macromolecules

d. C4B is encoded in the class II region of the MHC

e. The gene for C4B is duplicated or deleted in some individuals

e. The gene for C4B is duplicated or deleted in some individuals.

19

Which of the following is able to bind to C1q?

a. bacterial adhesins and toxoids

b. IgM and C-reactive protein

c. hemagglutinin

d. lipopolysaccharide

e. classical C3 convertase

b. IgM and C-reactive protein

20

IgM is particularly efficient at fixing complement because it ___.

a. is a much larger antibody than the other isotypes

b. has an extra CH domain

c. is made first in an immune response and therefore has fist access to C1q.

d. has five binding sites for C1q

e. has easy access to extravascular areas

d. has five binding sites for C1q

21

C3 convertase of the classical pathway is ___, whereas C3 convertase of the alternative pathway is ___.

a. C1a; C3bBb

b. C4bC2a; C3bBb

c. C3bCR1; C3bBb

d. C4bC2a; C3bCR1

e. C1a; C3bCR1

b C4bC2a; C3bBb

22

Complexes of IgG bound to soluble multivalent antigens can activate the classical pathway of complement, resulting in the deposition of ___ on the complex, targeting it for endocytic uptake by cells bearing ___.

a. C4b; CR2 and Fc receptors

b. C3b; CR2 and Toll-like receptors

c. C5-9; CR1 and Fc receptors

d. C3b; CR1 and Fc receptors

e. C2a; CR2 and Toll-like receptors

d. C3b; CR1 and Fc receptors

23

A distinguishing feature of FcgammaRIIB1 compared with FcgammaRIIA is ___.

a. its ability to activate cells and induce endocytosis

b. the existence of ITIMs in its cytoplasmic tails

c. its inability to bind to IgG1

d. its expression of NK cells

b. the eistence of ITIMs in its cytoplasmic tails

24

For IgG2 to be effective at stimulating uptake of IgG2-coated bacteria, ___.

a. an individual must express allotype H131 of FcgammaRIIA

b. an individual must express allotype R131 of FcgammaRIIA

c. the ITIMs of FcgammaRIIB2 must be non-functional

d. complement must be fixed on the surface of the barcterium

a. an individual must express allotype H131 of FcgammaRIIA

25

Naive B cells search for specific antigen displaced by follicular dendritic cells in primary follicles. Naive T cells, however, search for specific antigen presented by ___.

a. dendritic cells

b. subcapsular sinus macrophages

c. medullary sinus macrophages

d. centrocytes

e. tingible body macrophages

a. dendritic cells

26

Which of the following is consistent with the recently antigen-activated mast cell?

a. high levels of MHC class II molecules of the cell surface

b. the absence of prepackaged granules

c. the absence of IgE on the cell surface

d. high concentrations of C3b on the cell surface

e. the induction of antibody-dependent cell-mediated cytotoxicity

b. the absence of prepackaged granules

27

Some types of B-cell tumor have been treated with rituximab, an anti-CD20 monoclonal antibody, which exerts its effect through a mechanism known as___ involving the participation of NK cells.

a. degranulation

b. neutralization

c. opsonization

d. antibody-dependent cell-mediated cytoxicity

e. receptor-mediated endocytosis

d. antibody-dependent cell-mediated cytoxicity

28

Which of the following is a characteristic of follicular dendritic cells in the primary follicles of secondary lymphoid tissues?

a. They are bone marrow-derived hematopoietic cells

b. They provide a stable depository of intact antigens able to bind to B-cell receptors, and they have a large surface area as a result of forming dendrites.

c. they internalize immune complexes through CR2 receptor cross-linking

d. They produce cytokines that induce B cells to proliferate and become centroblasts.

b. They provide a stable depository of intact antigens able to bind to B-cell receptors, and they have a large surface area as a result of forming dendrites.

29

The B-cell co-receptor is composed of ___.

a. Igalpha; Igbeta; CD19

b. Igalpha; Igbeta; Lyn tyrosine kinase

c. CR2 (CD21); CD19; CD81

d. CD14; CD19; CD81

e. CD40; MHC class II; CED19

c. CR2 (CD21); CD19; CD81

30

C3d and iC3b are breakdown products of ___, which binds to ___ of the B-cell co-receptor

a. C3a; CR2

b. C3b; CR2

c. C3c; CD81

d. C3c; CD19

e. C3b; CD19

b. C3b; CR2

31

When bound to CR1, C3b is cleaved by ___, generating pathogen-associated B-cell co-receptor ligands.

a. factor I

b. CR2

c. C3d

d. CD19

e. Lyn

a. factor I

32

The Ig-alpha-associated tyrosine kinase ___ phosphorylates the cytoplasmic tail of CD19, which mediates signal transduction in activated B cells.

a. CD81

b. Blk

c. Fyn

d. Lyn

e. Syk

d. Lyn

33

A B cells sensitivity to antigen can be increased 1000 to 10,000-fold by ___.

a. simultaneously ligating the B-cell receptor and co-receptor

b. simultaneously ligating the B-cell receptor and Toll-like receptor

c. ligating the B-cell co-receptor and phosphorylating Ig-alpha ITAMs

d. increasing levels of Syk proteins in the vicinity of co-receptor ligation

e. ligating cytokine receptors on the B-cell surface

a. simultaneously ligating the B-cell receptor and co-receptor

34

The process that drives an increase in antibody affinity for antigen is known as ___.

a. apoptosis

b. affinity maturation

c. antibody-dependent cell-mediated cytotoxicity

d. opsonization

e. clonal expansion

b. affinity maturation

35

FcRn has which of the following characteristics?

a. It binds to monomeric IgA in acidified endocytic vesicles.

b. It transports IgG out of the blood into tissue across the endothelium; two molecules of FcRn are required to bind to each Fc region.

c. It is similar in structure to an MHC class II molecule.

d. It protects IgA from degradation by plasma proteases.

b. It transports IgG out of the blood into tissue across the endothelium; two molecules of FcRn are required to bind to each F region.

36

The process involving receptor-mediated transport of macromolecules from one side of a cell to the other is called

a. phagocytosis

b. exocytosis

c. transcytosis

d. signal transduction

e. opsonization

c. transcytosis

37

Of the following, which group of children is the most vulnerable to infection?

a. babies born at term

b. babies born prematurely

c. infants of 3-6 months

d. infants receiving first vaccination

e. babies receiving formula and not breast milk.

b. babies born prematurely

38

___ occurs as a result of influenza virus binding to oligosaccharide components on erythrocyte surfaces causing them to clump together.

a. Passive immunization

b. Opsonization

c. Hemagglutination

d. Neutralization

e. Complement activation

c. Hemagglutination

39

Bacteria use ___ to attach to the surface of cells during colonization.

a. hemagglutinins

b. toxins

c. breakdown products

d. anti-inflammatory molecules

e. adhesins

e. adhesins

40

Denatured toxin molecules called ___ are used to vaccinate individuals to stimulate the production of ___.

a. toxoids; neutralizing IgG antibodies

b. adhesins; neutralizing antibodies

c. toxoids; passive immunity

d. adhesins; complement proteins

e. toxoids; C-reactive protein

a. toxoids; neutralizing IgG antibodies

41

The disadvantage of having a longer hinge region in IgG3 compared with the other IgG subclasses is a reduction in tis serum half-life because of its susceptibility to ___.

a. increased proteolysis by serum proteases

b. clearance by erythrocytes via FcR binding

c. immune complex formation and deposition in kidney glomeruli

d. complement fixation and uptake by cells bearing receptor CR1

e. opsonization by neutrophils

a. increased proteolysis by serum proteases

42

Which of the following antibodies activate the classical pathway of complement?

a. IgM, IgG1, and IgG3

b. IgG1 and IgG2

c. IgD

d. IgG3 and IgG4

e. IgE

a. IgM, IgG1, and IgG3

43

The gamma chain of the FcgammaRI receptor is closely related to the ____, which contains ___.

a. FcRn; MHC class I-like structure

b. zeta chain of the T-cell receptor complex; ITAM motifs

c. gamma chain of the FcgammaRIII receptor; ITIM motifs

d. gamma chain of the FcalphaRI receptor; ITIM motifs

e. gamma chain of the FcepsilonRI receptor; ITIM motifs

b. zeta chain of the T-cell receptor complex; ITAM motifs

44

Of the Fc receptors for IgG, which one is similar to FcepsilonRI in its ability to bind antibody in the absence of antigen but does not transduce an activating signal until antigen cross-linking occurs?

a. FcgammaRI

b. FcgammaRIIA

c. FcgammaRIIB2

d. FcgammaRIIBI

e. FcgammaRIII

a. Fcgamma RI

45

Which of the following individuals would be most susceptible to fulminant meningococcal disease or septic shock when infected with Neisseria meningitidis?

a. homozygous for allotype H131 of IgG2

b. heterozygous for allotype H131 of IgG2

c. homozygous for allotype R131 of IgG2

d. heterozygous for allotype R131 of IgG2

e. All of the above would be equally susceptible to infections with Neisseria meningitidis.

c homozygous for allotype R131 of IgG2

46

Antibody-dependent cell-mediated cytotoxicity (ADCC) is carried out by ___ after cross-linking of IgG1 or IgG3 antibodies on ___ receptors.

a. NK cells; FcgammaRI

b. neutrophils; FcgammaRI

c. NK cells; FcgammaRIII

d. macrophages; FcgammaRIIB2

e. mast cells; FcepsilonRI

c. NK cells; FcgammaRIII

47

The symptoms of allergy and asthma are induced after cross-linking of IgE antibody on FcepsilonRI receptors found on the surface of ___.

a. basophils, eosinophils, and mast cells

b. B cells

c. macrophages

d. T cells

e. neutrophils

a. basophils, eosinophils, and mast cells

48

The FcalphaRI receptor binds to ___: antigen complexes and facilitates the phagocytosis of opsonized antigens.

a. dimeric IgA

b. IgM

c. IgE

d. IgG

e. monomeric IgA

e. monomeric IgA