CHAPTER 8
T Cell-Mediated Immunity
Questions
8–1
A. Identify three types of professional antigen-presenting cell.
B. How are they distributed in secondary lymphoid tissue?
C. Which kinds of antigen do they present efficiently to T cells?
8–2
A. Explain the functional differences between immature and mature dendritic cells.
B. Discuss why you think these functional changes should occur.
C. Give an example of an immature and a mature dendritic cell.
8–3
Why are Toll-like receptors (TLRs) important for adaptive immune responses?
8–4
Describe (A) the functions of macrophages in secondary lymphoid tissue, and (B) their
location(s).
8–5
Describe three distinct mechanisms by which naive CD8 T cells can be activated.
8–6
Which of the following describes an activated dendritic cell upon arriving in a lymph node?
a. Located in follicles and medulla of the lymph node
b. Associated mainly with antigen uptake and processing
c. Bears highly elaborated finger-like processes called dendrites
d. Expresses low levels of MHC class II molecules
e. Carries out apoptosis of lymphocytes.
8–7
Dendritic cells take up, process or present antigen by which of the following routes? (Select all
that apply)
a. Receptor-mediated endocytosis of bacteria using the mannose receptor
b. Macropinocytosis of soluble antigens
c. Uptake of viruses using Toll-like receptor TLR9
d. Cross-presentation from the MHC class II pathway to the MHC class I pathway
e. Cross-presentation from incoming infected dendritic cells to healthy resident dendritic
cells in secondary lymphoid tissue.
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8–8
Activated T cells express _____, which binds to B7 with twentyfold higher affinity for B7 than
CD28 and results in _____ of T cell activity and proliferation.
a. high-affinity IL-2 receptor; stimulation
b. CD40L; suppression
c. VLA-4; stimulation
d. CTLA4; suppression
e. Fas ligand; stimulation.
8–9
T cells failing to encounter specific antigen leave lymph nodes via the _________.
a. germinal center
b. bloodstream
c. high endothelial venules
d. afferent lymph
e. efferent lymph.
8–10
Naive lymphocytes homing to lymphoid tissue use _____ to bind to CD34 and GlyCAM-1 on
high endothelial venules.
a. L-selectin
b. CD2 (LFA-2)
c. ICAM-1
d. CCL21
e. CD28.
8–11
The co-stimulatory molecule _____ on professional antigen-presenting cells binds _____ on the
surface of naive T cells.
a. DC-SIGN; ICAM-3
b. B7; CD28
c. ICAM-1; LFA-1
d. MHC class II; T-cell receptor
e. MHC class II; CD4.
8–12
An adhesion molecule called _____ is expressed exclusively on activated dendritic cells and
binds to _____ on naive T cells in the T-cell areas of secondary lymphoid tissue.
a. DC-SIGN; ICAM-3
b. DEC205; ICAM-3
c. MHC class II; T-cell receptor
d. L selectin; GlyCAM-1
e. ICAM-1; LFA-1.
8–13
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In secondary lymphoid tissues dendritic cells are located in _____, whereas B cells are present in
_____.
a. lymphoid follicles; throughout the cortex and medulla
b. throughout the cortex and medulla; lymphoid follicles
c. throughout the cortex and medulla; cortical T-cell area
d. cortical T-cell areas; lymphoid follicles
e. lymphoid follicles; cortical T-cell areas.
8–14
The area of contact between membranes of a T cell and an antigen-presenting cell where a
clustering of protein–protein interactions occur is called a(n)
a. immunoreceptor tyrosine-based activation motif (ITAM)
b. polarization
c. cross-presentation center
d. granuloma
e. immunological synapse.
8–15
Clonal expansion and differentiation of naive T cells to effector T cells depends on the activation
of the transcription factor(s) _____ through a ZAP-70-mediated signal transduction pathway.
(Select all that apply.)
a. AP-1
b. IL-2
c. NF–B
d. NFAT
e. Ras.
8–16
Fos, a component of the transcription factor AP-1, is activated during T-cell signaling by a
process involving a GTP-binding protein called _____.
a. inositol trisphosphate
b. Ras
c. protein kinase C-
d. Lck
e. ZAP-70.
8–17
_____ is a second messenger in the T-cell signaling pathway leading to the activation of NFAT.
a. Diacylglycerol (DAG)
b. NF–B
c. Inositol triphosphate
d. Fos
e. Ras.
8–18
Co-stimulatory signals induced through CD28 cause(s) _____. (Select all that apply.)
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a. activation of Jun, a component of the AP-1 transcription factor
b. activation of protein tyrosine kinase ZAP-70
c. activation of protein tyrosine kinase Lck
d. requirement for only about 100 peptide:MHC complexes to activate a naive T cell
e. stabilization of IL-2 mRNA.
8–19
TH2 cytokines exert which of the following effects? (Select all that apply.)
a. production of neutralizing antibodies
b. B-cell differentiation
c. macrophage activation
d. production of opsonizing antibodies
e. release of cytotoxins by cytotoxic T cells
f. inflammation.
8–20
TH1 cytokines exert which of the following effects? (Select all that apply.)
a. production of neutralizing antibodies
b. B-cell differentiation
c. macrophage activation
d. production of opsonizing antibodies
e. release of cytotoxins by cytotoxic T cells
f. inflammation.
8–21
In the absence of a co-receptor (CD4 or CD8 for T helper cells or cytotoxic T cells,
respectively), T cells require _____ specific peptide:MHC complexes on the antigen-presenting
cell compared with interactions involving a co-receptor.
a. more
b. fewer
c. the same number.
8–22
Which of the following is a protein tyrosine kinase involved in T-cell activation culminating in
T-cell proliferation and differentiation?
a. AP-1
b. ZAP-70
c. NF–B
d. NFAT
e. Lck.
8–23
Binding of _____ to _____ induces T-cell proliferation and differentiation of activated T cells.
a. CD4; MHC class II
b. CD28; B7
c. LFA-1; ICAM-1
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d. IL-2; the high-affinity IL-2 receptor
e. IL-2; the low-affinity IL-2 receptor.
8–24
Factors thought to have an influence on the differentiation of CD4 T cells into either TH1 or TH2
include (select all that apply):
a. the cytokines made during the preceding innate immune response
b. the type of antigen-presenting cell interacting with the T cell
c. the cytokines made by the antigen-presenting cell interacting with the T cell
d. the number of specific peptide:MHC complexes presented by the antigen-presenting cell
e. the release of lytic granules from cytotoxic T cells.
8–25
Expression of IFN- is induced in a CD4 TH1 cell under the direction of the transcription factor
______.
a. T-bet
b. FoxP3
c. AP-1
d. GATA-3
e. NFAT.
8–26
IL-4 is induced in a CD4 TH2 cell under the direction of the transcription factor _____.
a. T-bet
b. FoxP3
c. AP-1
d. GATA-3
e. NFAT.
8–27
Tuberculoid leprosy is characterized by a _____-type response where patients _____.
a. TH2; usually survive
b. TH2; eventually die
c. TH1; usually survive
d. TH1; eventually die
e. Treg; eventually die.
8–28
Cytokine receptors are associated with cytoplasmic protein kinases called _____, which become
activated when the cytokine receptors bind to their respective cytokines.
a. ZAP-70
b. STATs
c. Lck
d. ITAMS
e. JAKs.
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8–29
Which of the following is not produced by cytotoxic T cells?
a. IFN-
b. CD40 ligand
c. TNF-
d. lymphotoxin
e. Fas ligand.
8–30
Which of the following is not produced by TH1 cells?
a. IL-10
b. TGF-
c. CD40 ligand
d. TNF-
e. lymphotoxin.
8–31
Which of the following is not produced by TH2 cells?
a. IL-4
b. CD40 ligand
c. TGF-
d. IFN-
e. IL-10.
8–32
Signal transducers and activators of transcription (STATs) are _____ that are phosphorylated by
_____.
a. transcription factors; JAKs
b. protein kinases; other STATs
c. cytokine receptors; JAKs
d. cytokines; cytokine receptors
e. transcription factors; Lck.
8–33
The process by which cytotoxic T cells kill their targets involves _____. (Select all that apply.)
a. inducing the target cell to undergo necrosis
b. inducing apoptosis (programmed cell death) in the cytotoxic T cell
c. DNA fragmentation in lengths of multiples of 200 base pairs in the target cell
d. shedding of membrane-bound vesicles and shrinking of the target cell
e. release of granzyme, perforin, and granulysin by the cytotoxic T cell
f. engaging Fas ligand on the target cell with Fas on the cytotoxic T-cell surface.
8–34
The etiological agent responsible for leprosy is Mycobacterium leprae, which survives and
replicates within the vesicular system of macrophages. Explain the difference between
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tuberculoid leprosy and lepromatous leprosy in the context of T-cell differentiation and effector
function.
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Answers
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