Chapter 6 quiz

Question 1

Which of the following cell-surface markers differentiates hematopoietic stem cells from other cell constituents in the bone marrow?

a. pre-B-cell receptor
b. BAFF receptor
c. CD34
d. CD4
e. membrane-bound stem-cell factor (SCF)

Answer 1

c. CD34

Question 2

Which of the following is characteristic of a large pre-B cell?

a. VDJ is successfully rearranged and mu heavy chain is made.
b. V–J is rearranging at the light-chain locus.
c. mu heavy chain and lambda or kappa light chain is made.
d. V is rearranging to DJ at the heavy-chain locus.
e. D–J is rearranging at the heavy-chain locus

Answer 2

a. VDJ is successfully rearranged and mu heavy chain is made.

Question 3

Which of the following statements is correct?

a. The κ light-chain genes rearrange before the heavy-chain genes.
b. The κ light-chain genes rearrange before the λ light-chain genes.
c. The λ light-chain genes rearrange before the heavy-chain genes.
d. The λ light-chain genes rearrange before the κ light-chain genes.
e. The μ heavy-chain genes rearrange first and then the λ light-chain genes rearrange

Answer 3

b. The κ light-chain genes rearrange before the λ light-chain genes.

Question 4

Immature B cells develop into B cells in the

a. subendosteum
b. bone marrow
c. thymus
d. blood
e. secondary lymphoid organs

Answer 4

e. secondary lymphoid organs

Question 5

Large pre-B cells are characterized by which of the following?

a. They do not express CD19 at the cell surface.
b. Rearrangement of light-chain genes commences.
c. Nonproductive rearrangement of both heavy-chain loci has already occurred.
d. Allelic exclusion of the immunoglobulin light-chain loci has already occurred.
e. The mu chain is assembled with VpreB-lambda5.

Answer 5

e. The mu chain is assembled with VpreB-lambda5.

Question 6

All hematopoietic stem cells express

a. CD34
b. CD127
c. CD19
d. VpreBlambda5
e. Pax-5

Answer 6

a. CD34

Question 7

The latest stages of late pro-B-cell development are recognized by the association of a surrogate light chain with a mu chain. The surrogate light chain is composed of _______.

a. E2A and EFB
b. Ig-alpha and Ig-beta
c. VpreB and lambda5
d. RAG-1 and RAG-2
e. Pax-5 and CD19

Answer 7

c. VpreB and lambda5

Question 8

Which of the following is not paired with its correct complement?

a. N nucleotides: more abundant in rearranged heavy-chain genes than in rearranged light-chain
genes
b. second checkpoint in B-cell development: assembly of a functional B-cell receptor
c. receptor editing: exchange of light chain for one that is not self-reactive
d. first checkpoint in B-cell development: selection by the pre-B-cell receptor
e. large pre-B-cell stage: constitutive expression of RAG-1 and RAG-2 proteins.

Answer 8

e. large pre-B-cell stage: constitutive expression of RAG-1 and RAG-2 proteins.

Question 9

Which of the following would occur after the production of a functional μ chain as a pre-B-cell receptor?

a. RAG proteins are degraded.
b. The chromatin structure of the heavy-chain locus is reorganized to prevent gene rearrangement.
c. Transcription of the RAG1 and RAG2 genes ceases.
d. There is allelic exclusion of a second mu chain.
e. All of the above would occur.

Answer 9

e. All of the above would occur.

Question 10

An important advantage of having two gene loci (kappa and lambda) for the light chain is ________.

a. that the likelihood of a successful rearrangement of light-chain genes increases
b. that immunoglobulins are homogeneous and not heterogeneous in mature B cells
c. that different effector functions are conferred by the two different light-chain loci
d. that surrogate light-chain transcription cannot compete with kappa and lambda transcription and
enables B-cell development
e. all of the above

Answer 10

a. that the likelihood of a successful rearrangement of light-chain genes increases

Question 11

A defect in which of the following proteins blocks B-cell development at the pre-B-cell stage, resulting in almost no circulating antibodies in individuals with this defect?

a. IL-7 receptor
b. terminal deoxynucleotidyltransferase (TdT)
c. Pax-5
d. Bruton’s tyrosine kinase (Btk)
e. CD19

Answer 11

d. Bruton’s tyrosine kinase (Btk)

Question 12

The consequence of allelic exclusion at the immunoglobulin loci ensures that _____.

a. B-cell receptors have a low-avidity binding
b. B cells express antigen receptors of a single specificity and homogeneous B-cell receptors bind more effectively to antigen
c. hybrid immunoglobulins are formed
d. all functional copies of a gene are expressed
e. heterogeneous B-cell receptors bind more effectively to antigen

Answer 12

b. B cells express antigen receptors of a single specificity and homogeneous B-cell receptors bind more effectively to antigen

Question 13

A developing B cell unable to generate a productive rearrangement on any of the four light-chain loci will undergo _____________.

a. self-renewal
b. apoptosis
c. allelic exclusion
d. malignant transformation
e. differentiation into a B-1 cell

Answer 13

b. apoptosis

Question 14

All of the following participate in signal transduction in developing B cells except:

a. terminal deoxynucleotidyl transferase (TdT)
b. FLT3
c. CD19
d. Igα and Igβ
e. Bruton’s tyrosine kinase (Btk)

Answer 14

a. terminal deoxynucleotidyl transferase (TdT)

Question 15

Negative selection of developing B cells ensures that ___________.

a. there is not an overabundance of circulating B cells that would compete with other important cell
types in the circulation
b. only antigen-activated B cells leave the bone marrow
c. clonal expansion of B cells does not occur in the absence of infection
d. B-cell receptors that bind to normal constituents of the body do not emerge
e. B cells do not leave secondary lymphoid tissues

Answer 15

d. B-cell receptors that bind to normal constituents of the body do not emerge

Question 16

Receptor editing occurs _____.

a. in the bone marrow to establish self-tolerance of the B-cell repertoire
b. after encounter with foreign antigen in secondary lymphoid organs
c. in mature B cells
d. to establish self-reactivity of the B-cell repertoire
e. to express an excess of IgM over IgD on the surface of mature B cells

Answer 16

a. in the bone marrow to establish self-tolerance of the B-cell repertoire

Question 17

Which of the following statements about the IgD made by B cells of upper respiratory mucosa is not true?

a. These antibodies bind to airborne bacteria such as Haemophilus influenzae.
b. lambda light chains are used almost exclusively by these IgD antibodies.
c. Two-thirds of these IgD antibodies possess kappa light chains.
d. These IgD antibodies recruit basophils and induce the secretion of antibacterial peptides.
e. kappa light chains are used almost exclusively by these IgD antibodies.

Answer 17

c. Two-thirds of these IgD antibodies possess kappa light chains.

Question 18

All of the following are associated with the development of Burkitt’s lymphoma except:

a. The expression of Myc protein is perturbed.
b. A chromosomal translocation involving a proto-oncogene and an immunoglobulin gene occurs.
c. Overproduction of the Bcl-2 protein prolongs the lifetime of B-lineage cells.
d. Cell division restraints on mutated B cells are lifted.
e. In addition to a chromosomal translocation event, mutations elsewhere in the genome are usually
involved.

Answer 18

c. Overproduction of the Bcl-2 protein prolongs the lifetime of B-lineage cells.

Question 19

Which of the following is a characteristic of B-2 cells?

a. They are sometimes referred to as CD5 B cells.
b. They comprise only 5% of the B-cell repertoire.
c. In adults, they are renewed by cell division in the peripheral circulation.
d. They are located primarily in secondary lymphoid organs.
e. They are not dependent on T helper cells for activation.

Answer 19

d. They are located primarily in secondary lymphoid organs.

Question 20

Identify the mismatched pair of chemokine and the cells that secrete it.

a. CCL19: lymph-node dendritic cells
b. CXCL13: follicular dendritic cells
c. CCL21: stromal cells of secondary lymphoid tissues
d. All of the above are correctly matched.
e. None of the above is correctly matched.

Answer 20

d. All of the above are correctly matched.

Question 21

Plasma cells have all of the properties listed except ______________.

a. they rapidly proliferate in secondary lymphoid follicles
b. they secrete antibody and they are terminally differentiated B cells
c. they no longer express MHC class II molecules
d. they cease expressing membrane-bound immunoglobulin
e. differentiation into plasma cells occurs after migration from germinal centers to other sites in lymphoid tissue and bone marrow

Answer 21

a. they rapidly proliferate in secondary lymphoid follicles

Question 22

All of the following events occur within germinal centers except:

a. production of memory B cells
b. isotype switching
c. centroblasts arise from activated B cells
d. B cells are activated by CD4 helper T cells
e. affinity maturation

Answer 22

d. B cells are activated by CD4 helper T cells

Question 23

In which location would plasma cells not be present?

a. bone marrow
b. afferent lymphatic vessels
c. medullary cords of lymph nodes
d. lamina propria of gut-associated lymphoid tissues
e. efferent lymphatic vessels

Answer 23

b. afferent lymphatic vessels

Question 24

Immunological tolerance in the B-cell repertoire is called _______ tolerance when it develops in primary lymphoid organs, and _______ tolerance when it is induced outside the bone marrow.

a. primary; secondary
b. apoptotic; anergic
c. stromal; follicular
d. receptor-mediated; systemic
e. central; peripheral

Answer 24

e. central; peripheral

Question 25

When producing monoclonal antibodies, why is it important to use as a fusion partner a myeloma cell that is unable to produce its own immunoglobulin?

a. To ensure that allelic exclusion of mu chain occurs normally.
b. To ensure that the antibodies are homogeneous and able to make strong bivalent attachments to multivalent antigens.
c. To ensure that the monoclonal antibodies are not autoreactive.
d. To provide a greater opportunity for making a successful rearrangement at the light-chain locus.
e. To ensure that antibodies are secreted and not membrane-bound.

Answer 25

b. To ensure that the antibodies are homogeneous and able to make strong bivalent attachments to multivalent antigens.

Question 26

The proto-oncogene _______ is associated with the development of Burkitt’s lymphoma.

a. BCL-2
b. Myc
c. CD5
d. CD19
e. BTK

Answer 26

b. Myc

Question 27

Which of the following characterizes the B-1 cells that develop prenatally?

a. They lack N nucleotides.
b. They possess polyspecificity for bacterial polysaccharide antigens.
c. They arise early in embryonic development preceding the development of the majority subset of B
cells.
d. They have little or no IgD on the cell surface.
e. All of the above.

Answer 27

e. All of the above.

Question 28

What is the fate of an immature B cell that encounters and has specificity for self antigen?

a. If further heavy-chain and light-chain gene rearrangements are possible, it undergoes apoptosis.
b. Somatic hypermutation.
c. Decrease in production of IgD.
d. Continued rearrangement of heavy-chain genes.
e. Continued rearrangement of light-chain genes.

Answer 28

e. Continued rearrangement of light-chain genes.

Question 29

Which of the following pertains to the fate of immature B cells that have specificity for univalent self antigens?

a. The cells acquire a state of unresponsiveness called anergy.
b. IgD is retained in the cytosol.
c. IgD on the cell surface activate the B cell when bound to self antigen.
d. The cells have a much longer life-span than mature B cells.
e. The cells die by apoptosis.

Answer 29

a. The cells acquire a state of unresponsiveness called anergy.

Question 30

The circulatory route through a lymphoid tissue for both immature B cells and mature B cells that do not encounter specific antigen is:

a. bloodstream –> HEV of lymphoid cortex –> primary lymphoid follicle –> efferent lymphatic vessel
b. afferent lymphatic vessel –> primary lymphoid follicle –> HEV of lymphoid cortex –> efferent lymphatic vessel
c. afferent lymphatic vessel –> medullary cords –> primary lymphoid follicle –> efferent lymphatic vessel
d. primary lymphoid follicle –> HEV of lymphoid cortex –> afferent lymphatic vessel –> efferent lymphatic vessel
e. bloodstream –> afferent lymphatic vessel –> HEV of lymphoid cortex –> efferent lymphatic vessel.

Answer 30

a. bloodstream –> HEV of lymphoid cortex –> primary lymphoid follicle –> efferent lymphatic vessel