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Immuno > Chapter 8 > Flashcards

Chapter 8 Flashcards

1
Q

Which of the following contributes to the activation of naive T cells?

a. neutrophils
b. B cells
c. macrophages
d. dendritic cells
e. basophils

A

dendritic cells

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2
Q

Macrophages exhibit all of the following characteristics except _____.

a. they trap and degrade pathogens in secondary lymphoid organs
b. they deliver co-stimulatory signals to naive T cells needed for T-cell priming
c. they migrate from sites of infection to nearby secondary lymphoid organs
e. they remove and degrade apoptotic lymphocytes from secondary lymphoid tissues
f. they reside in both the cortex and medulla of lymph nodes

A

they migrate from sites of infection to nearby secondary lymphoid organs

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3
Q

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

A

bears highly elaborated finger-like processes called dendrites

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4
Q

Dendritic cells take up, process or present antigen by all of the following routes except _____.

a. receptor-mediated endocytosis of bacteria
b. macropinocytosis of bacteria or viruses
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
f. delivery of viral peptides from cytosol to endoplasmic reticulum during viral infection

A

a. receptor-mediated endocytosis of bacteria
b. macropinocytosis of bacteria or viruses
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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5
Q

Activated T cells express _____, which binds to B7 with 20 times higher affinity 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

A

CTLA4; suppression

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6
Q

Which of the following is associated with immature dendritic cells in the skin before their activation?

a. Toll-like receptors
b. CTLA4
c. CCR7
d. DC-SIGN
e. ICAM-3

A

Toll-like receptors

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7
Q

All of the following are correctly matched except _____.

a. TH1: T-bet
b. Treg: FoxP3
c. IL-12: dendritic cells
d. TH17: RORγT
e. TH2: Bcl6

A

TH2: Bcl6

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8
Q

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

A

L-selectin

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9
Q

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

A

B7; CD28

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10
Q

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. CD2; LFA-3
c. MHC class II; T-cell receptor
d. L-selectin; GlyCAM-1
e. ICAM-1; LFA-1

A

DC-SIGN; ICAM-3

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11
Q

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

A

immunological synapse

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12
Q

All of the following are included in the central supramolecular activation complex (c-SMAC) except _____.

a. CD4 or CD8
b. ICAM-1
c. CD28
d. T-cell receptor
e. PKC-θ

A

ICAM-1

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13
Q

Talin is best described as a _____.

a. protein tyrosine kinase
b. transcriptional activator
c. cytoskeletal protein
d. pro-inflammatory cytokine
e. cytokine receptor that associates with Janus kinases (JAKs)

A

cytoskeletal protein

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14
Q

The primary effect of inositol trisphosphate (IP3) during T-cell activation is to _____.

a. cause an increase in cytosolic calcium concentration
b. activate phospholipase C-γ
c. activate a MAP kinase cascade
d. facilitate the differentiation of immature effector T cells
e. align the microtubule-organizing center toward the antigen-presenting cell

A

cause an increase in cytosolic calcium concentration

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15
Q

Which of the following is not a transcription factor, a component of a transcription factor, or an activator of transcription?

a. Fos
b. AP-1
c. NFκB
d. NFAT
e. JAKs
f. FoxP3
g. GATA-3
h. T-bet
i. STATs
j. Jun
k. Bcl6
l. RORγT

A

JAKs

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16
Q

The enzyme that generates diacylglycerol (DAG) and inositol trisphosphate (IP3) from phosphatidylinositol bisphosphate (PIP2) is _____.

a. protein kinase C-θ (PKC-θ)
b. calcineurin
c. phospholipase C-γ (PLC-γ)
d. protein tyrosine kinase ZAP-70
e. protein tyrosine kinase Lck

A

phospholipase C-γ (PLC-γ)

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17
Q

All of the following statements regarding interleukin-2 (IL-2) or its receptor are true except _____.

a. The low-affinity IL-2 receptor is a membrane-bound heterodimer composed of α and β chains.
b. IL-2 production increases approximately 100-fold if a co-stimulatory signal is delivered.
c. T-cell proliferation occurs upon binding of IL-2 to the high-affinity IL-2 receptor.
d. The high-affinity IL-2 receptor is assembled after T-cell activation.
e. Rapamycin is an immunosuppressive drug that inhibits signaling of IL-2 through the IL-2 receptor.

A

The low-affinity IL-2 receptor is a membrane-bound heterodimer composed of α and β chains.

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18
Q

If a non-professional antigen-presenting cell that lacks co-stimulatory molecules presents peptide:MHC complexes to a T cell specific for that peptide, then _____.

a. the T cell delivers a signal to the non-professional antigen-presenting cell to activate the expression of co-stimulatory molecules.
b. the T cell begins to express the α chain of the IL-2 receptor.
c. the T cell differentiates into a TH1 cell.
d. T-cell tolerance occurs as a result of anergy.
e. the T cell is more heavily reliant on signals transmitted through CD4 or CD8 in order to become activated.

A

T-cell tolerance occurs as a result of anergy.

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19
Q

Which of the following statements regarding leprosy is false?

a. It is caused by the bacterium Mycobacterium leprae.
b. Disease progression is influenced depending on whether the immune response is polarized toward either a TH1 or TH2 response.
c. The tuberculoid form of leprosy is associated with localized inflammation and granuloma formation.
d. In lepromatous leprosy, the patient makes a TH2 response that clears the mycobacteria from the body.
e. The less severe form of leprosy presents with high levels of IL-2 and IFN-γ produced by responding T cells.

A

In lepromatous leprosy, the patient makes a TH2 response that clears the mycobacteria from the body.

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20
Q

Which of the following statements is false regarding CD8 T cells?

a. CD8 T cells have only one effector function, which is cytotoxicity.
b. Compared with naive CD4 T cells, naive CD8 T cells have more stringent requirements for co-stimulatory activity.
c. Effector CD8 cells require co-stimulation to kill their target cells.
d. The most potent antigen-presenting cell for naive CD8 T cells is the dendritic cell.

A

Effector CD8 cells require co-stimulation to kill their target cells.

21
Q

An important way in which effector T cells differ from naive T cells is that _____.

a. the cell-surface level of LFA-1 is lower on effector T cells
b. L-selectin is upregulated during differentiation of effector T cells
c. cellular proliferation occurs after effector T cells leave the secondary lymphoid tissues
d. the provision of co-stimulatory signals is not required to induce a response by effector T cells
e. effector T cells do not recirculate between lymph, blood, and secondary lymphoid tissues

A

the provision of co-stimulatory signals is not required to induce a response by effector T cells

22
Q

All of the following indicate correct intermolecular associations except _____.

a. Janus kinases (JAKs): serglycin
b. L-selectin: GlyCAM-1
c. VLA-4: VCAM-1
d. JAKs: signal transducers and activators of transcription (STATs)

A

Janus kinases (JAKs): serglycin

23
Q

During cytokine signaling, _____ translocate(s) to the nucleus and direct(s) the upregulation of gene expression.

a. perforin
b. STATs
c. CD40 ligand
d. TGF-β
e. CXCL2

A

STATs

24
Q

Which of the following cytokines is secreted by both CD8 T cells and TH1 cells? (Select all that apply.)

a. IL-4
b. IL-5
c. IFN-γ
d. TNF-α
e. IL-13
f. lymphotoxin (LT)

A

c. IFN-γ

f. lymphotoxin (LT)

25
Q

Which of the following cytokines is not secreted by TH2 cells? (Select all that apply.)

a. IFN-γ
b. IL-4
c. IL-5
d. IL-10
e. TGF-β
f. lymphotoxin (LT)

A

a. IFN-γ

f. lymphotoxin (LT)

26
Q

In a person with lepromatous leprosy, the lesions would contain mRNA for _____.

a. lymphotoxin (LT)
b. IL-2
c. IL-5
d. IFN-γ
e. granulysin

A

IL-5

27
Q

The release of lytic granules from cytotoxic T cells is aimed specifically at infected target cells while preserving the integrity of neighboring, uninfected cells. This is best explained by the observation that _____.

a. only target cells bearing appropriate peptide:MHC class I complexes are susceptible to necrosis
b. redistribution of lytic granules in the T cell delivers them to confined areas on the target cell in contact with the T cell
c. regulatory T cells deliver survival signals to uninfected neighboring cells that renders them resistant to cytotoxins
d. the amount of cytotoxins in a given cytotoxic T cell is so limited that only the cell closest to the T cell will succumb to the effects of perforin and granzyme
e. uninfected cells are highly resistant to the effects of cytotoxins

A

redistribution of lytic granules in the T cell delivers them to confined areas on the target cell in contact with the T cell

28
Q

All of the following statements refer to regulatory T cells except ____.

a. they produce anti-inflammatory cytokines
b. they express elevated levels of CD25
c. they express FoxP3
d. they enhance the production of new effector T cells
e. they suppress the function of existing T cells

A

they enhance the production of new effector T cells

29
Q

Identify the mismatched pair.

a. TFH cells: Bcl6
b. TH1: GATA3
c. TH1 cells: IFN-\gamma
d. TH2: IL-4
e. Treg: TGF-\beta

A

TH1: GATA3

30
Q

Which of the following is incorrect regarding sphingosine 1-phosphate (S1P) and its receptor?

a. It is a lipid that has chemotactic activity.
b. S1P gradients are established in lymph nodes with lowest concentrations in T-cell areas.
c. CD69 upregulates S1P receptor expression on the surface of naive T cells.
d. S1P is synthesized by all cells.

A

CD69 upregulates S1P receptor expression on the surface of naive T cells.

31
Q

Which of the following is produced by CD8 T cells?

a. IL-10
b. TGF-β
c. IFN-γ
d. IL-4
e. IL-17

A

IFN-γ

32
Q

Which of the following is not produced by T follicular helper (TFH) cells?

a. CD4
b. IL-4
c. IFN-γ
d. TNF-α
e. IL-21

A

TNF-α

33
Q

Which of the following is not produced by TH17 cells?

a. ICOS (inducible T-cell co-stimulator)
b. IL-17
c. CD4
d. IL-21
e. STAT3

A

ICOS (inducible T-cell co-stimulator)

34
Q

Which of the following is a feature of regulatory T cells (Treg)? (Select all that apply.)

a. Treg express CD8 and control effector cells by inducing apoptosis.
b. Treg express high levels of CD25 (IL-2 receptor α chain) and secrete pro-inflammatory cytokines such as IFN-γ.
c. Physical association between Treg and their target cells is mandatory for Treg function.
d. By interacting with dendritic cells in secondary lymphoid tissue, Treg prevent the interaction and activation of naive T cells.
e. Treg secrete TGF-β and suppress effector T-cell function.

A

c. Physical association between Treg and their target cells is mandatory for Treg function.
d. By interacting with dendritic cells in secondary lymphoid tissue, Treg prevent the interaction and activation of naive T cells.
e. Treg secrete TGF-β and suppress effector T-cell function.

35
Q

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

A

efferent lymph

36
Q

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. NFκB
d. NFAT
e. Ras

A

a. AP-1
c. NFκB
d. NFAT

37
Q

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-θ
d. Lck
e. ZAP-70

A

Ras

38
Q

_____ is a second messenger in the T-cell signaling pathway leading to the activation of NFAT.

a. diacylglycerol (DAG)
b. NFκB
c. inositol trisphosphate
d. Fos
e. Ras

A

inositol trisphosphate

39
Q

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 of

A

more

40
Q

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. NFκB
d. NFAT
e. calcineurin

A

ZAP-70

41
Q

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
d. IL-2; the high-affinity IL-2 receptor
e. IL-2; the low-affinity IL-2 receptor

A

IL-2; the high-affinity IL-2 receptor

42
Q

Expression of IFN-γ 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

A

T-bet

43
Q

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

A

GATA-3

44
Q

Tuberculoid leprosy is characterized by a _____-type response in which patients _____.

a. TH2; usually survive
b. TH2; eventually die
c. TH1; usually survive
d. TH1; eventually die
e. Treg; eventually die

A

TH1; usually survive

45
Q

Many 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

A

JAKs

46
Q

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

A

transcription factors; JAKs

47
Q

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

A

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

48
Q

Which of the following characteristics permits activated CD8 T cells to destroy any cell type harboring viable and replicating pathogens such as viruses?

a. The pathogen is located in extracellular spaces.
b. CD8 T cells enable macrophages to kill intracellular pathogens.
c. Pathogen-derived peptides bind MHC class I molecules in endocytic vesicles found ubiquitously in most cell types.
d. MHC class II molecules are expressed ubiquitously by most nucleated cells.
e. MHC class I molecules are expressed ubiquitously by most nucleated cells.

A

MHC class I molecules are expressed ubiquitously by most nucleated cells.

49
Q

Parents who were distantly related to each other brought their 11-week-old infant Kristen to the emergency room after she had a seizure accompanied by a persistently high fever and running nose. Her liver and spleen were palpable (hepatosplenomegaly). Laboratory tests revealed abnormally high levels of lymphocytes, and of the cytokines IFNγ, TNF-α, and IL-6. Conversely, levels of hemoglobin and platelets were abnormally low. Bone marrow aspiration showed the presence of macrophages containing phagocytosed red blood cells and numerous large granular lymphocytes. Molecular analysis was carried out to confirm the physician’s suspicion of a congenital immunodeficiency. A frameshift mutation in the perforin gene PRF1 was found on both chromosomes. Kristen was diagnosed with the rare, potentially life-threatening disease known as familial hemophagocytic lymphohistiocytosis (FHL). Cytotoxic and aggressive immunosuppressive chemotherapy was administered followed by a matched unrelated hematopoietic stem cell transplant. Two years later Kristen is a healthy toddler. Which of the following would not be consistent with the etiology of FHL?

a. impaired cytotoxic activity of CD8 T cells
b. inhibition of transcriptional activators required for IL-2 synthesis
c. inability to kill virus-infected cells
d. persistent activation of CD8 T cells causing secretion of large amounts of IFN-γ
e. IFN-γ activation of macrophages which in turn drives the production of IL-6, TNF-α, and other pro-inflammatory molecules

A

inhibition of transcriptional activators required for IL-2 synthesis

Immuno (16 decks)

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