Exam 3 Review Flashcards
Which of the following is the first stage of T-cell receptor gene rearrangement in alpha:beta T cells?
a. V-alpha –> D-alpha
b. D-alpha –> J-alpha
c. V-beta –> D-beta
d. D-beta –> J-beta
e. V-alpha –> J-alpha
D-beta –> J-beta
The function of negative selection of thymocytes in the thymus is to eliminate _____.
a. single-positive thymocytes
b. double-positive thymocytes
c. alloreactive thymocytes
d. autoreactive thymocytes
e. apoptotic thymocytes
autoreactive thymocytes
All of the following participate in signal transduction in developing B cells except:
a. terminal deoxynucleotidyl transferase (TdT)
b. FLT3
c. CD19
d. Igalpha and Igbeta
e. Bruton tyrosine kinase (Btk)
terminal deoxynucleotidyl transferase (TdT)
The proto-oncogene _______ is associated with the development of Burkitt s lymphoma.
a. BCL-2
b. Myc
c. CD5
d. CD19
e. BTK
Myc
Once a thymocyte has productively rearranged a beta-chain gene, which of these events cannot occur subsequently?
a. beta binds to pTalpha and is expressed on the cell surface with the CD3 complex and zeta chain.
b. Rearrangement of beta-, gamma- and delta-chain genes ceases as a result of the suppression of expression of RAG-1 and RAG-2.
c. The pre-T cell proliferates and produces a clone of cells all expressing an identical beta chain.
d. Expression of CD34 and CD2 gives rise to double-positive thymocytes.
e. Alpha-, gamma-, delta-chain loci rearrange simultaneously.
Expression of CD34 and CD2 gives rise to double-positive thymocytes.
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.
large pre-B-cell stage: constitutive expression of RAG-1 and RAG-2 proteins.
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
afferent lymphatic vessels
Thymocytes that are not positively selected _____________.
a. undergo genetic reprogramming and differentiate into a different cell type
b. are exported to the periphery, where they are phagocytosed by macrophages
c. make up about 98% of developing thymocytes and die by apoptosis in the thymic cortex
d. are eliminated because of their reactivity with self antigens
e. try out different beta chains to acquire reactivity with self-MHC molecules
make up about 98% of developing thymocytes and die by apoptosis in the thymic cortex
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
they rapidly proliferate in secondary lymphoid follicles
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
VpreB and lambda5
_______ of thymocytes is necessary to produce a T-cell repertoire capable of interacting with self-MHC molecules.
a. positive selection
b. negative selection
c. apoptosis
d. receptor editing
e. isotype switching
positive selection
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.
VDJ is successfully rearranged and mu heavy chain is made.
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
bloodstream –> HEV of lymphoid cortex –> primary lymphoid follicle –> efferent lymphatic vessel
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.
The mu chain is assembled with VpreB-lambda5.
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
central; peripheral
Genetic deficiencies in all of the following would impair the development of a fully functional T-cell repertoire except ________.
a. RAG-1 or RAG-2
b. Notch1
c. Pax-5
d. IL-7 receptor (CD127)
e. TAP-1 or TAP-2
Pax-5
Immediately after positive selection __________.
a. the thymocyte reaches maturity and is exported to the periphery
b. RAG proteins are degraded and are no longer synthesized
c. receptor editing commences to eliminate reactivity against self antigens
d. the developing thymocyte acquires a double-negative phenotype
e. expression of pTalpha is repressed
RAG proteins are degraded and are no longer synthesized
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
B cells express antigen receptors of a single specificity and homogeneous B-cell receptors bind more effectively to antigen
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.
Overproduction of the Bcl-2 protein prolongs the lifetime of B-lineage cells.
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.
The cells acquire a state of unresponsiveness called anergy.
All hematopoietic stem cells express ___________.
a. CD34
b. CD127
c. CD19
d. VpreBlambda5
e. Pax-5
CD34
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
All of the above
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 tyrosine kinase (Btk)
e. CD19
Bruton tyrosine kinase (Btk)
Healthy individuals have approximately ____ of CD4 T cells compared with CD8 T cells.
a. one quarter the number
b. half the number
c. equal numbers
d. twice the number
e. four times the number
twice the number
