Deck 17: Failures of the Immune Response

Question 1

Some hosts are subject to numerous infections by pyogenic (pus-forming)bacteria.This is indicative of a defect in

A)The complement pathway
B)The production of interferon
C)Antigen presentation
D)Chemotactic factors

Answer 1

The complement pathway

Question 2

Some people are resistant to HIV infection because of mutations in _____ on the surface of host cells.

A)CD4
B)Co-stimulatory molecules
C)Co-receptors
D)Class II MHC molecules
E)CD8

Answer 2

Co-receptors

Question 3

Explain what accounts for the high level of mutation associated with HIV. Why does this pose a problem for the host?

Answer 3

HIV is a retrovirus that uses reverse transcriptase to synthesize a double-stranded DNA copy of the RNA genome.This enzyme lacks the proofreading activity that is associated with other DNA polymerases,and as a result,numerous mutations occur during viral replication.This is problematic for the host as these mutations help HIV evade host defenses,and to develop rapid resistance to antiviral drugs and escape drug therapy.

Question 4

Which of the following would most likely produce an anaphylactic response in a patient allergic to the substance?

A)Pollen
B)Peanuts
C)Dust mites
D)Cat dander

Question 5

HIV uses a complex of glycoproteins on its surface,including _____,to bind to the surface of T cells,dendritic cells,and macrophages.

A)CD4 and CD8
B)Gp120 and gp41
C)CXCR4 and CCR5
D)CCL3, CCL4, and CCL5

Question 6

Which of the following is not a characteristic of primary immunodeficiencies?

A)They cause overwhelming and frequent infections early in childhood
B)Can result from defects in the complement system
C)They are caused by recessive gene defects
D)They affect humoral but not cell-mediated immune responses

Question 7

Which malignancy is commonly associated with HIV infection?

A)Breast cancer
B)Prostate cancer
C)Kaposi's sarcoma
D)T-cell lymphoma

Question 8

Wiskott-Aldrich syndrome is characterized by

A)Loss of phagocyte function
B)Thymic aplasia
C)Susceptibility to encapsulated bacterial infections
D)Lack of T cells and B cells
E)The presence of a functional actin cytoskeleton

Question 9

Which of the following body fluids contains the highest number of infectious HIV particles per milliliter of fluid from infected individuals?

A)Saliva
B)Vaginal-cervical fluid
C)Cerebrospinal fluid
D)Breast milk
E)Tears

Question 10

Which of the following is false?

A)Myasthenia gravis results from the formation of autoantibodies specific for neurotransmitter receptors
B)Systemic lupus erythematosus is characterized by the formation of anti-DNA antibodies
C)Rheumatic fever follows influenza infections when antibodies against the virus cross-react with host components
D)Tolerance is the process whereby self-reactive T and B cells are inactivated or eliminated
E)Autoimmune responses are controlled by specialized CD25-positive T cells called regulatory T cells

Question 11

Which of the following statements is false?

A)Autoimmunity can be induced by infection, drugs, and toxins
B)Some individuals are genetically predisposed to the development of autoimmune disease
C)Autoimmune diseases are classified according to whether they are organ-specific or systemic
D)Graves' disease affects the nervous system

Question 12

Type IV hypersensitivity reactions are caused by

A)Immune complexes of soluble antigens and IgG
B)Antigen-specific T cells
C)Eosinophil activation
D)Anti-drug IgG antibodies
E)IgE cross-linking on mast cell surfaces

Question 13

During anaphylactic shock,prompt attention is required,and the injection of _____ provides immediate relief from the life-threatening symptoms presented.

A)Anti-histamine
B)Leukotriene
C)Epinephrine (adrenaline)
D)Prostaglandin
E)Cytokine

Question 14

Which of the following is a mismatched pair?

A)Reverse transcriptase: cDNA
B)Co-receptor: CD4
C)Sub-acute encephalitis: AIDS dementia
D)Opportunistic pathogen: Pneumocystis (carinii) jiroveci
E)Integrase: long terminal repeats

Question 15

All of the following are associated with anaphylactic shock except

A)Decrease in blood pressure
B)Bronchoconstriction
C)Systemic vascular permeability
D)Itchy, watery eyes
E)Activation of mast cells in connective tissue

Question 16

The "AIDS dementia" that some people with HIV get is most associated with what body system?

A)Nervous system
B)Lymphatic system
C)Circulatory system
D)Cranial system

Question 17

If an individual is diagnosed with DiGeorge syndrome,then

A)T cells fail to develop
B)Class II MHC molecules are not expressed
C)Cytokines are not produced
D)There is increased susceptibility to Neisseria spp. infections owing to defects in complement
E)They cannot form phagolysosomes

Question 18

B-cell immunodeficiencies cause all of the following except

A)Failure to protect mucosal surfaces with neutralizing antibody
B)Increased susceptibility to viral infections
C)Inability to opsonize encapsulated bacteria
D)Loss of toxin neutralization function
E)Severe combined immunodeficiency

Question 19

Rheumatic fever is an autoimmune disease commonly caused by what bacterial species?

A)Staphylococcal species
B)Streptococcal species
C)Listeria species
D)Mycobacterium species

Question 20

Which of the following is not a characteristic of HIV?

A)Enveloped
B)Retrovirus
C)Single-stranded DNA
D)Sexually transmitted
E)Encodes reverse transcriptase

Question 21

Describe the three phases of HIV infection.

Question 22

Summarize the sequence of events during HIV infection,beginning with adsorption of the virion on the host cell surface and ending with the release of virions from the infected cell.

Question 23

Describe the appearance of lymph nodes during the early asymptomatic phase and the late symptomatic phase of HIV infection