Question 1

Which of the following mechanisms does NOT contribute to the generation of a cytolytic T lymphocyte (CTL) response to a viral infection?

Accepted Answer

A)  Dendritic cells phagocytose infected cells or viral particles and present them to naive CD8+ T cells via the class I MHC pathway.
B)  Dendritic cells are infected with the virus and present viral peptides to naive CD8+ T cells via the class I MHC pathway.
C)  CTLs are directly activated by CD40L expressed on activated helper T cells through CD40.
D)  Helper T cells secrete cytokines,such as interleukin-2,that promote the proliferation and differentiation of CD8+ T cells.
E)  Helper T cells activate infected antigen-presenting cells (APCs) via the CD40 ligand-CD40 pathway,and the activated APCs present viral peptides to naive CD8+ T cells via the class I MHC pathway.

Question 2

Differentiation of TH2 cells from naive precursor cells is dependent on which of the following?

Accepted Answer

A)  Toll-like receptor (TLR) ligands
B)  T-bet
C)  Interleukin-12
D)  GATA-3
E)  Interferon- α\alphaα

Question 3

The mechanisms by which TH1 cells protect against microbes include all of the following EXCEPT:

Accepted Answer

A)  Secretion of interferon (IFN) - γ\gammaγ which activates microbicidal functions of macrophages
B)  Expression of CD40 ligand,which binds to CD40 on macrophages and activates them
C)  Secretion of IFN- γ\gammaγ ,which promotes B cell production of opsonizing antibodies
D)  Secretion of lymphotoxin and tumor necrosis factor,which enhance neutrophil killing of ingested microbes
E)  Release of granzyme B,which stimulates apoptosis of bacteria  E

Question 4

A 23-year-old man who was recently infected by the HIV virus volunteered for investigative studies of his immune response to the virus.Investigators identified cytolytic T lymphocytes (CTLs) in the patient's blood that recognized a particular peptide derived from a protein encoded by the HIV gag gene.Six months later,viral isolates from the patient showed point mutations in the gag gene sequence encoding that peptide.Which of the following statements about the HIV gag mutations is most likely to be correct?

Accepted Answer

A)  The patient's CTL response to the virus provided selective pressure for the emergence of virus carrying the mutation.
B)  The CTL that recognized the original gag-encoded peptide will still be able to recognize the mutated Gag peptide.
C)  The CTLs specific for the original Gag peptide were incapable of killing HIV-infected cells.
D)  The gag mutation will enhance the ability of natural killer cells to recognize and kill HIV infected cells.
E)  The gag mutations have more relevance to the viral evasion of the antibody response rather than the CTL responsE.

Question 5

Activated macrophages perform all of the following functions EXCEPT:

Accepted Answer

A)  Inhibition of fibroblast proliferation and angiogenesis within damaged tissues
B)  Production of lysosomal enzymes and reactive oxygen species that kill phagocytosed microbes
C)  Presentation of antigen to helper T cells
D)  Secretion of inflammatory cytokines such as tumor necrosis factor and interleukin-1
E)  Production of nitric oxide,which helps kill microorganisms

Question 6

Which of the following statements about cell-mediated immunity (CMI) is NOT true?

Accepted Answer

A)  Deficiencies in CMI result in susceptibility to infections by viruses and intracellular bacteriA.
B)  CMI can be adoptively transferred by injecting serum from one individual to another.
C)  Delayed-type hypersensitivity (DTH) is not a protective response against intracellular bacteria such as Mycobacterium tuberculosis.
D)  The principal form of CMI that protects against viral infections is mediated by CD8+ cytolytic T lymphocytes.
E)  Phagocytes are essential in the effector phase of CMI responses to bacteria such as Listeria monocytogenes.

Question 7

The induction phase of a cell-mediated immune response includes which of the following events?

Accepted Answer

A)  CD4+ T cell secretion of interferon- γ\gammaγ  leading to macrophage activation
B)  CD8+ T cell lysis of a virally infected cell
C)  Clonal expansion of CD8+ T cells within a lymph node
D)  Migration of CD4+ effector T cells from blood vessels into a tissue site of infection
E)  Migration of a naive CD4+ T cell from the thymic medulla into the circulation  C

Question 8

Which pair of molecules is a component of cytolytic T lymphocyte (CTL) granules and is important in the mechanism of CTL killing of target cells?

Accepted Answer

A)  Perforin and Fas ligand
B)  P-selectin and tumor necrosis factor
C)  Major basic protein and granzyme B
D)  C9 and interferon- γ\gammaγ 
E)  Perforin and granzyme B

Question 9

Which of the following molecules is NOT important in the interaction between a cytolytic T lymphocyte and a target cell?

Accepted Answer

A)  B7-1
B)  ICAM-1
C)  LFA-1
D)  T cell receptor
E)  Class I MHC

Question 10

Which of the following comparisons between TH1 and TH2 cells is true?

Accepted Answer

A)  TH1 cells produce interleukin (IL) -1 but not IL-2,and TH2 cells produce IL-2 but not IL-1.
B)  TH1 cells are class I major histocompatibility complex (MH
C)  restricted,and TH2 cells are class II MHC restricted.
C)  The chemokine receptors CXCR3 and CCR5 are more highly expressed on TH2 cells than on TH1 cells.
D)  TH2 cells are more likely to bind to E-selectin and P-selectin on endothelial cells than are TH1 cells.
E)  TH1 cells produce interferon (IFN) - γ\gammaγ  but not IL-4,and TH2 cells produce IL-4 but not IFN- γ\gammaγ    E

Exam 7: Effector Mechanisms of T-Cell Mediated Immunity

Which of the following mechanisms does NOT contribute to the generation of a cytolytic T lymphocyte (CTL) response to a viral infection?

Correct Answer
verified

Differentiation of T_H2 cells from naive precursor cells is dependent on which of the following?

Correct Answer
verified

The mechanisms by which T_H1 cells protect against microbes include all of the following EXCEPT:

Correct Answer
verified
E

Correct Answer
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Activated macrophages perform all of the following functions EXCEPT:

Correct Answer
verified

Which of the following statements about cell-mediated immunity (CMI) is NOT true?

Correct Answer
verified

The induction phase of a cell-mediated immune response includes which of the following events?

Correct Answer
verified
C

Which pair of molecules is a component of cytolytic T lymphocyte (CTL) granules and is important in the mechanism of CTL killing of target cells?

Correct Answer
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Which of the following molecules is NOT important in the interaction between a cytolytic T lymphocyte and a target cell?

Correct Answer
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Which of the following comparisons between T_H1 and T_H2 cells is true?

Correct Answer
verified
E

Exam 7: Effector Mechanisms of T-Cell Mediated Immunity

Which of the following mechanisms does NOT contribute to the generation of a cytolytic T lymphocyte (CTL) response to a viral infection?

Correct AnswerverifiedShow Answer

Differentiation of TH2 cells from naive precursor cells is dependent on which of the following?

Correct AnswerverifiedShow Answer

The mechanisms by which TH1 cells protect against microbes include all of the following EXCEPT:

Correct AnswerverifiedE

Correct AnswerverifiedShow Answer

Activated macrophages perform all of the following functions EXCEPT:

Correct AnswerverifiedShow Answer

Which of the following statements about cell-mediated immunity (CMI) is NOT true?

Correct AnswerverifiedShow Answer

The induction phase of a cell-mediated immune response includes which of the following events?

Correct AnswerverifiedC

Which pair of molecules is a component of cytolytic T lymphocyte (CTL) granules and is important in the mechanism of CTL killing of target cells?

Correct AnswerverifiedShow Answer

Which of the following molecules is NOT important in the interaction between a cytolytic T lymphocyte and a target cell?

Correct AnswerverifiedShow Answer

Which of the following comparisons between TH1 and TH2 cells is true?

Correct AnswerverifiedE

Correct Answer
verified

Differentiation of T_H2 cells from naive precursor cells is dependent on which of the following?

Correct Answer
verified

The mechanisms by which T_H1 cells protect against microbes include all of the following EXCEPT:

Correct Answer
verified
E

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
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C

Correct Answer
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Correct Answer
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Which of the following comparisons between T_H1 and T_H2 cells is true?

Correct Answer
verified
E