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Immunology Practice Questions Exam 1-3 > Exam #1 > Flashcards

Exam #1 Flashcards

1
Q

Which of the following is an example of secondary lymphoid tissue?

a. Liver
b. Spleen
c. Bone marrow
d. Thymus

A

b. Spleen

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2
Q

What is the normal life span of a naive lymphocyte?

a. 5-7 days
b. 1-2 weeks
c. 3-10 hours
d. 1-3 months

A

d. 1-3 months

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3
Q

A cell expressing which of the following will be observed interacting with B cells, macrophages, and dendritic cells?

a. CD4
b. CD34
c. CD8
d. CD25

A

a. CD4

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4
Q

What is the purpose of chemokines?

a. Stimulation of growth and differentiation of T cells
b. Cellular homing to certain tissues
c. Mediation of antigen presentation
d. Stimulation of growth and differentiation of B cells

A

b. Cellular homing to certain tissues

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5
Q

At what B cell stage would you expect it to be getting ready to interact with a T cell in a lymph node?

a. Immature B cell
b. Mature naive B cell
c. Mature activated B cell
d. Pre-B cell

A

b. Mature naive B cell

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6
Q

At what T cell stage would you expect it to be in the infected tissue?

a. Pre-T cell
b. Immature T cell
c. Mature naive T cell
d. Active T cell

A

d. Active T cell

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7
Q

What is the ligand for CD44?

a. Lipopolysaccharide
b. Flagellin
c. Mannose
d. Hyaluronic acid

A

d. Hyaluronic acid

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8
Q

Chemokine receptors are:

a. G protein coupled receptors
b. Tyrosine kinases
c. Ligand gated ion channels
d. Beta barrel pores

A

a. G protein coupled receptors

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9
Q

Do naive T cells or activated T cells gain the ability to leave the lymph node first?

a. Definitely naive T cells
b. No way man; it’s activated T cells

A

a. Definitely naive T cells

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10
Q

Which of the following does not immediately result from TLR binding a ligand?

a. T cell activation
b. ROS production
c. Phagocytosis

A

a. T cell activation

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11
Q

LPS is recognized by what type of TLR?

a. TLR2/6
b. TLR1/2
c. TLR4
d. TLR5

A

c. TLR4

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12
Q

LTA is recognized by what type of TLR?

a. TLR2/6
b. TLR1/2
c. TLR4
d. TLR5

A

a. TLR2/6

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13
Q

What inflammatory caspase is activated by NLRs?

a. caspase-1
b. caspase-3
c. caspase-8
d. caspase-9

A

a. caspase-1

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14
Q

Mice without SR (scavenger receptors) are

a. more susceptible to infection by microbial pathogens
b. more susceptible to die via necrosis
c. less susceptible to infection by microbial pathogens
d. able to compensate with NLRs and C-type Lectin family receptors

A

a. more susceptible to infection by microbial pathogens

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15
Q

C-type lectin receptors recognize which substances?

a. microbial mannose
b. N-acetylglucosamine
c. Sialic acid
d. Both A and B are correct
e. Both A and C are correct

A

d. Both A and B are correct

Remember: C-type lectins recognize microbial mannose, N-acetylglucosamine, and beta-glucan. These are all foreign substances that are not normally found in the human body. Silica acid and galactose are substances that are normally found in the human body so it would be bad if C-type lectins recognized these substances.

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16
Q

Which of the following cytokines most strongly activates endothelial cells to express E-selectins?

a. IL-1
b. TNF
c. IFN-gamma
d. IL-6

A

b. TNF

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17
Q

Which of the following cytokines most strongly induces fever?

a. IL-1
b. TNF
c. IFN-gamma
d. IL-6

A

a. IL-1

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18
Q

Which of the following cytokines most strongly induces synthesis of acute phase proteins?

a. IL-1
b. TNF
c. IFN-gamma
d. IL-6

A

d. IL-6

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19
Q

Which TLR would be best at recognizing the West Nile virus in the body?

a. TLR5
b. TLR9
c. TLR2
d. TLR3

A

d. TLR3

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20
Q

Which of the following regions of the antibody contributes to antigen recognition?

a. VL chain
b. CL chain
c. Fc Fragment
d. Hinge region

A

a. VL chain

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21
Q

Digestion of an antibody by pepsin yields which of the following?

a. one protein segment that can bind one antigen
b. one protein segment that can bind two antigens
c. two protein segments that can bind one antigen
d. two protein segments that can bind two antigens

A

b. one protein segment that can bind two antigens

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22
Q

How many constant regions does one IgM heavy chain have?

a. 1
b. 2
c. 3
d. 4

A

d. 4

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23
Q

Describe the affinity and avidity of IgM.

a. IgM has high affinity and low avidity
b. IgM has high affinity and high avidity
c. Ig M has low affinity and high avidity
d. IgM has low affinity and low avidity

A

c. IgM has low affinity and high avidity

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24
Q

IgM isotype switching to IgA results in the change of what?

a. light chain isotype switching
b. heavy chain isotype switching
c. TCR chain isotype switching
d. IgA isotype switching

A

b. heavy chain isotype switching

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25
Q

What cytokine is required for isotope switching to IgG?

a. IL-4
b. IL-2
c. TGF-beat
d. IFN-gamma

A

d. IFN-gamma (G in gamma stands for IgG!)

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26
Q

A few weeks after baby is born, she suddenly becomes sick. The destruction of what Ab, obtained from her mother in the womb, results in inadequate neutralization of the toxin?

a. IgG
b. IgE
c. IgM
d. IgD

A

a. IgG

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27
Q

You ingested a toxin. What Ag is responsible for neutralizing that toxin in your GI tract?

a. IgA
b. IgD
c. IgE
d. IgM

A

a. IgA

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28
Q

What Ab(s) is (are) found on the surface of mature B cells that have not yet been activated?

a. IgA
b. IgD
c. IgE
d. IgM
e. A and B are correct
f. B and C are correct
g. B and D are correct

A

g. B and D are correct

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29
Q

Class 1 MHCs are encoded by what genes?

a. HLA-A, HLA-B, HLA-C
b. HLA-DP, HLA-DQ, HLA-DR
c. HLA-A, HLA-B, HLA-D
d. HLA-DP, HLA-DM, HLA-DQ

A

a. HLA-A, HLA-B, HLA-C

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30
Q

Class 2 MHCs are found on what cells?

a. all nucleated cells
b. only professional APCs
c. B cells, dendritic cells, and macrophages
d. monocytes
e. both B and C are correct

A

e. both B and C are correct

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31
Q

The CD8 coreceptor recognizes what type of cells?

a. cells expressing MHC Class 1
b. cells expressing MHC Class 2
c. cells expressing Beta-2 microglobulins
d. cells expressing CD3 complex

A

a. cells expressing MHC Class 1
c. cells expressing Beta-2 microglobuins

Technically beta-2 micoglobulins are part of MHC class 1 so A and C are both correct

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32
Q

Th1 cells fight what type of infection?

a. extracellular infection
b. intracellular infection
c. helminths infection
d. CTL infection

A

b. intracellular infection

33
Q

Th2 cells make IL-4. In the presence of IL-4, what Ab is produced by plasma cells?

a. IgA
b. IgD
c. IgE
d. IgM

A

c. IgE

34
Q

What are the components of the TCR complex?

a. MHC class 1, CD8, linear peptide
b. MHC class 2, CD4, linear peptide
c. alpha/beta TCR, CD3, and Zeta chains
d. delta/gamma TCR, CD40L, and Zeta chains

A

c. alpha/beta TCR, CD3, and Zeta chains

35
Q

What are the signaling components of the TCR complex?

a. alpha/beta TCR
b. CD3
c. zeta chains
d. CD40
e. B and C

A

e. B and C

36
Q

Which of the following cell types cannot express Class I MHC?

a. T cells
b. Hepatocytes
c. B cells
d. Red blood cells

A

d. Red blood cells

37
Q

You have a cell sample stained to see all CD3+ cells. What do you stain for next in order to identify cells that respond to extracellular pathogens?

a. CD4
b. CD8
c. Class I MHC
d. Class II MHC

A

a. CD4

38
Q

A macrophage phagocytizes a pathogen. It then escapes into the cytoplasm. After antigen processing, in what MHC will the antigen be expressed?

a. Class I
b. Class II

A

a. Class I

39
Q

Which of the following is NOT a quality of an activated dendritic cell?

a. Ability to present antigen to T cells
b. Expression of Fc and mannose receptors
c. Expression of costimulatory molecules (B7, etc)
d. Increased expression of MHC molecules

A

b. Expression of Fc and mannose receptors

40
Q

Insulin is an example of what type of receptor?

a. nuclear hormone receptor
b. non-receptor tyrosine kinase based receptor
c. GPCR
d. tyrosine kinase receptor

A

d. tyrosine kinase receptor

41
Q

What type of receptor does glucagon utilize?

a. nuclear hormone receptor
b. non-receptor tyrosine kinase based receptor
c. GPCR
d. tyrosine kinase receptor

A

c. GPCR

Chemokines and PGs also use GPCRs

42
Q

CD4/CD8 are associated with what family of kinases?

a. Src family
b. Syk family
c. Tec family
d. ZAP-70 family

A

a. Src family (c-Src, Lyn, Fyn, Lck)!!!!

b. Syk family (Syk and ZAP-70)
c. Tec family(Tec, Btk, Itk)
d. ZAP-70 family

43
Q

SH3 domains recognize what characteristic of polypeptides?

a. phosphotyrosine residues
b. proline-rich stretches
c. PIP3 and other phosphatidylinositol-derived lipids
d. phosphatidylserine residues

A

b. proline-rich stretches

44
Q

What recognizes phosphotyrosine residues? What recognizes phosphatidylinositol-derived lipids?

A

SH2 & PH

45
Q

What components of the TCR complex can signal?

a. TCR
b. CD3
c. Zeta chains
d. alpha and beta chains

A

b. CD3
c. Zeta chains

*Remember the tail end of the TCR itself is too short for ITAMs/ITIMs to be associated with it.

46
Q

How many signaling chains are present in the TCR complex?

a. 2
b. 4
c. 6
d. 8
e. 10

A

c. 6 (4 chains from CD3 and 2 from zeta chains)

47
Q

How many ITAMs are found in the TCR complex?

a. 2
b. 4
c. 6
d. 8
e. 10

A

e. 10 (4 in the CD3 complexes, 6 on the zeta chains)

48
Q

A previously healthy 8-year-old boy is infected with an upper respiratory tract virus for the first time. During the first few hours of infection, which one of the following events occurs?

a. The adaptive immune system responds rapidly to the virus and keeps the viral infection under control.
b. The innate immune system responds rapidly to the viral infection and keeps the viral infection under control.
c. Passive immunity mediated by maternal antibodies limits the spread of infection.
d. B and T lymphocytes recognize the virus and stimulate the innate immune response.
e. The virus causes malignant transformation of respiratory mucosal epithelial cells, and the malignant cells are recognized by the adaptive immune system.

A

b. The innate immune system responds rapidly to the viral infection and keeps the viral infection under control.

49
Q

Which of the following is a unique property of the adaptive immune system?

a. Highly diverse repertoire of specificities for antigens
b. Self-nonself discrimination
c. Recognition of microbial structures by both cell-associated and soluble receptors
d. Protection against viral infections
e. Responses that have the same kinetics and magnitude on repeated exposure to the same microbe.

A

a. Highly diverse repertoire of specificities for antigens

50
Q

A standard treatment of animal bite victims, when there is a possibility that the animal was infected with the rabies virus, is administration of human immunoglobulin preparations containing anti-rabies virus antibodies. Which type of immunity would be established by this treatment?

a. active humoral immunity
b. passive humoral immunity
c. active cell-mediated immunity
d. passive cell-mediated immunity
e. innate immunity

A

b. passive humoral immunity

51
Q

At 15 months of age, a child received a measles-mumps-rubella vaccine (MMR). At age 22, she is living with a family in Mexico that has not been vaccinated and she is exposed to measles. Despite the exposure, she does not become infected. Which of the following properties of the adaptive immune system is best illustrated by this scenario?

a. specificity
b. diversity
c. specialization
d. memory
e. nonreactivity to self

A

d. memory

52
Q

The two major functional classes of effector T lymphocytes are:

a. Helper T lymphocytes and cytotoxic T lymphocytes
b. Natural killer cells and cytotoxic T lymphocytes
c. Memory T cells and effector T cells
d. Helper cells and antigen-presenting cells
e. Cytotoxic T lymphocytes and target cells

A

a. Helper T lymphocytes and cytotoxic T lymphocytes

53
Q

Which of the following best describes clonal expansion in adaptive immune responses?

a. Increased number of different lymphocyte clones, each clone specific for a different antigen during the course of an infection.
b. Increased number of different lymphocyte clones, each clone specific for a different antigen during development of the immune system, before exposure to antigen
c. Increased number of lymphocytes with identical specificities, all derived from a single lymphocyte due to nonspecific stimuli from the innate immune system
d. Increased number of lymphocytes with identical specificities, all derived from a single lymphocyte stimulated by a single antigen.
e. Increased size of the lymphocytes of a single clone due to antigen-induced activation of the cells.

A

d. Increased number of lymphocytes with identical specificities, all derived from a single lymphocyte stimulated by a single antigen.

54
Q

Which of the following statements about the innate immune system is NOT true?

a. Innate immunity is present in all multicellular organisms, including plants and insects.
b. Deficiencies in innate immunity markedly increase host susceptibility to infection, even in the setting of an intact adaptive immune response.
c. Innate immunity is better suited for eliminating virulent, resistant microbes than is adaptive immunity.
d. The innate immune response can be divided into recognition, activation, and effector phases.
e. The innate immune response against microbes influences the type of adaptive immune response that develops.

A

c. Innate immunity is better suited for eliminating virulent, resistant microbes than is adaptive immunity.

55
Q

Toll-like receptors (TLRs) are a family of homologous receptors expressed on many cell types and are involved in innate immune responses. Ten different mammalian TLRs have been identified, and several ligands for many of these receptors are known. Which of the following is a TLR ligand?

a. Single-stranded RNA
b. Transfer RNA
c. Double-stranded DNA
d. Unmethylated CpG DNA
e. Heterochromatin

A

d. Unmethylated CpG DNA

56
Q

The signaling pathways triggered by Toll-like receptors typically result in activation of which of the following pairs of transcription factors?

a. NFAT and T-bet
b. AP-1 and GATA-3
c. Fos and STAT-6
d. NFkB and AP-1
e. Lck and Jun

A

d. NFkB and AP-1

57
Q

Which of the following is a receptor on macrophages that is specific for a structure produced by bacteria but not mammalian cells?

a. CD36 (scavenger receptor)
b. Fc receptor
c. Complement receptor
d. Mannose receptor
e. ICAM-1

A

d. Mannose receptor

58
Q

A vaccine administered in the autumn of one year may protect against the prevalent strain of influenza virus that originated in Hong Kong that same year, but it will not protect against another strain of influenza virus that originated in Russia. This phenomenon illustrates which property of the adaptive immune system?

a. Specificity
b. Loss of memory
c. Specialization
d. Cultural diversity
e. Self-tolerance

A

a. Specificity

59
Q

Which of the following can be accurately called a cytokine?

a. A cell surface antigen receptor on lymphocyte
b. An antibody secreted by a B cell
c. A protein secreted by a T lymphocyte that activates a macrophage
d. A lipid secreted by a Natural Killer cell that activates a B cell
e. A nuclear protein that regulates lymphocyte gene expression

A

c. A protein secreted by a T lymphocyte that activates a macrophage

60
Q

According to the clonal selection hypothesis, which of the following is correct?

a. Lymphocyte specificity is determined by exposure to an antigen
b. Clones of lymphocytes specific for antigens develop prior to exposure to the antigens
c. Antigen binding to a lymphocyte receptor selects that lymphocyte to die
d. Antigen binding to secreted antibody stimulates proliferation of the B cell that secreted the antibody
e. Each clone of lymphocytes express receptors for many different antigens

A

b. Clones of lymphocytes specific for antigens develop prior to exposure to the antigens

61
Q

Which of the following cell types is a phagocyte?

a. Plasma cell
b. Neutrophil
c. Mast cell
d. Natural killer cell
e. T lymphocyte

A

b. Neutrophil

62
Q

A 52-year-old man who receives radiation therapy and cytotoxic drugs for treatment of cancer sustains significant damage to his bone marrow. Which of the following changes will most likely occur?

a. Decreased production of monocytes but not B lymphocytes
b. Decreased production of B lymphocytes but not T lymphocytes
c. Decreased production of neutrophils and monocytes but not B lymphocytes
d. Decreased production of B and T lymphocytes, monocytes, neutrophils and red blood cells
e. Normal production of all blood cells due to compensatory extramedullary hematopoiesis

A

d. Decreased production of B and T lymphocytes, monocytes, neutrophils and red blood cells

63
Q

In DiGeorge syndrome, the thymus fails to develop. Which of the following characterizes the immunodeficiency state in this syndrome?

a. Deficiency in monocytes and tissue macrophages
b. Defect in naive B cell activation and antibody production in response to bacterial polysaccharides
c. Deficiency in T lymphocytes and associated defects in cell-mediated immunity
d. Normal numbers of naive T cells that cannot be activated by antigen
e. Deficiency in B cell maturation

A

c. Deficiency in T lymphocytes and associated defects in cell-mediated immunity

64
Q

Tissue macrophages are derived from which type of circulating blood cell?

a. Polymorphonuclear leukocyte
b. Small lymphocyte
c. Monocyte
d. Basophil
e. Lymphoblast

A

c. Monocyte

65
Q

A 5-year-old boy with recurrent infections is discovered to have a genetic defect that impairs B cell maturation. Which of the following abnormalities is most likely to be found in this patient?

a. Small thymus
b. Absence of follicles in lymph nodes and spleen
c. Enlarged tonsils
d. Diminished parafollicular zones in lymph nodes
e. Hypocellular bone marrow

A

b. Absence of follicles in lymph nodes and spleen

66
Q

A drug that blocks the function of the chemokine receptor CCR7 would result in which of the following abnormalities?

a. Reduced numbers of T cells in lymph nodes
b. Absence of B cell follicles in the spleen
c. Reduced blood neutrophil count
d. Absence of follicular dendritic cells in lymph node follicles
e. Thin thymic cortex

A

a. Reduced numbers of T cells in lymph nodes

67
Q

Migration of leukocytes out of the blood into tissues mainly occurs in which type of vessel?

a. Arteries
b. Arterioles
c. Capillaries
d. Venules
e. Veins

A

d. Venules

68
Q

Which of the following accurately describe the function of the selectin family of adhesion molecules?

a. Selectins support low affinity rolling of leukocytes on endothelial cells
b. Endothelial selectins increase their affinity for binding to leukocytes in response to chemokines
c. Selectins guide migration of leukocytes though interendothelial junctions
d. Selectins are expressed only on naïve T cells
e. Selectins play a direct role in clonal selection

A

a. Selectins support low affinity rolling of leukocytes on endothelial cells

69
Q

A child with a mutation in the gene encoding one of the polypeptide chains of the integrin LFA-1 (CD11aCD18) suffers from recurrent serious bacterial and fungal infections, and the sites of infection contain few inflammatory leukocytes. Which of the following accurately describes a required function of the LFA-1 integrin that is missing in this child?

a. LFA-1 on endothelial cells binds to carbohydrate ligands on neutrophils and monocytes, causing these leukocytes to stably arrest on the endothelial surface.
b. LFA-1 on neutrophils and monocytes binds to ICAM-1 on endothelial cells causing the leukocytes to stably arrest on the endothelial surface.
c. LFA-1 on leukocytes binds to chemokines in tissues, which direct leukocytes to migrate into sites of infection
d. LFA-1 on endothelial cells binds to VCAM-1 on T cells, which supports migration of activated T cells into tissues
e. LFA-1 on neutrophils binds to ICAM-1 on bacterial cell walls, which supports phagocytosis of the bacteria.

A

b. LFA-1 on neutrophils and monocytes binds to ICAM-1 on endothelial cells causing the leukocytes to stably arrest on the endothelial surface.

70
Q

Which of the following is one of the major functions of chemokines in the immune system?

a. Increase affinity of leukocyte selectins for their ligands on endothelial cells.
b. Stimulate proliferation of B cells in response to antigen
c. Increase vascular permeability during the innate immune response to microbes
d. Maintain the spatial separation of B and T lymphocytes within lymphoid tissues
e. Form pores in bacterial membranes

A

d. Maintain the spatial separation of B and T lymphocytes within lymphoid tissues

71
Q

Which of the following statements correctly describes the migratory behavior of naïve T lymphocytes?

a. They recirculate from blood into lymph nodes via high endothelial venules, and back into blood via lymphatics
b. They recirculate from blood into inflamed tissues via activated post capillary venules, and back into blood via lymphatics
c. They migrate into the thymus via high endothelial venules, where they mature into effector T cells, which then enter the blood via lymphatics
d. They are stationary within lymph nodes and do not migrate
e. After maturation in the thymus, they migrate into the blood via draining lymphatics and enter the spleen via high endothelial venules

A

a. They recirculate from blood into lymph nodes via high endothelial venules, and back into blood via lymphatics

72
Q

Fingolimod is a drug used to treat autoimmune disease, which blocks the function of sphingosine-1 phosphate (S1P) by binding to its receptor S1PR1. Patients treated with fingolimod become lymphopenic, i.e. they have low numbers of lymphocytes in the blood. Why?

a. S1P binding to S1PR1 is required for T cell maturation in the thymus
b. S1P binding to S1PR1 stimulates lymphocyte clonal expansion
c. S1P binding to S1PR1 blocks lymphocyte migration out of the blood into lymph nodes
d. S1P binding to S1PR1 inhibits lymphocyte apoptosis
e. S1P binding to S1PR1 on lymphocytes is required for exit of lymphocytes from lymphoid tissues

A

e. S1P binding to S1PR1 on lymphocytes is required for exit of lymphocytes from lymphoid tissues

73
Q

Which of the following is not a function of the innate immune system?

a. Rapidly respond to microbial infections by promoting acute inflammation
b. Respond to viral infections by inducing the expression of type I interferons
c. Respond to microbial infections by inducing expression of T cell costimulators on antigen presenting cells
d. Respond to damaged and dying host cells by inducing acute inflammation
e. Respond to microbial infections by inducing a state of long lived memory that prevents repeat infections by the same microbe

A

e. Respond to microbial infections by inducing a state of long lived memory that prevents repeat infections by the same microbe

74
Q

Which of the following statements about the recognition receptors of the innate immune system, such as Toll like receptors, is correct?

a. They are encoded by genes produced by somatic recombination of gene segments that are separated in inherited germline DNA
b. Each clone of macrophages express a unique set of these receptors that differs in specificity from those receptors on all other clones of macrophages
c. They recognize pathogen associated molecular patterns, such as viral nucleic acids, bacterial cell wall constituents, and terminal mannose residues.
d. They function to neutralize microbes, but do not initiate signal transduction pathways that activate cells.
e. They undergo somatic mutation and affinity maturation in response to microbial antigens.

A

c. They recognize pathogen associated molecular patterns, such as viral nucleic acids, bacterial cell wall constituents, and terminal mannose residues.

75
Q

Which of the following is a proinflammatory cytokine of major importance in innate immunity that has been successfully targeted by drugs to treat rheumatoid arthritis (RA)?

a. Tumor necrosis factor (TNF)
b. Transforming growth factor-β (TGF-β)
c. Interleukin 10
d. Interleukin 2
e. Interferon γ

A

b. Transforming growth factor-β (TGF-β)

76
Q

Toll like receptors (TLRs) located in endosomal membranes of cells recognize which of the following?

a. Nucleic acids
b. Bacterial cell wall lipotechoic acid
c. Bacterial cell wall lipopolysaccharide
d. Uric acid crystals
e. Peptides containing N-formylmethionyl residues

A

a. Nucleic acids

Endosomal TLR-3,-7, and -9, recognize dsRNA, ssRNA, and CpG dinucleotides which are components of ingested viruses (dsRNA, ssRNA) and other microbes (unmethylated CpG-rich oligonucleotides). Bacterial cell wall lipotechoic acid and lipopolysaccharide are recognized by plasma membrane TLRs. Uric acid crystals are recognized by cytosolic NLR proteins in inflammasomes, and bacterially derived peptides containing N-formylmethionyl residues are recognized by the plasma membrane fmet-leu-phe receptor.

77
Q

All of the following molecules are opsonins that facilitate efficient phagocytosis of microbes by neutrophils and macrophages EXCEPT:

a. C3b
b. C5a
c. C-reactive protein
d. IgG
e. Mannose-binding lectin

A

b. C5a

C5a is a peptide released after cleavage of C5 protein upon activation of the complement cascade. It stimulates the influx of neutrophils to the site of infection, thus acting as a chemoattractant, not as an opsonin. C3b (covalently bound to microbes on which complement activation has taken place) and IgG bound to antigen, are potent opsonins, because phagocytes have receptors for both C3b and the Fc region of IgG. C-reactive protein and mannose-binding lectin also can coat microbes and be recognized by phagocyte receptors; thus they serve as opsonins.

78
Q

Which of the following is a feature of Natural Killer (NK) cells?

a. They express antigen receptors that directly bind antigens on the surface of microbes
b. They are activated by recognizing microbial peptides bound to host class I MHC molecules
c. They kill virally infected cells by a perforin/granzyme dependent mechanism
d. Upon activation, they secrete abundant interleukin-4
e. They secrete natural IgM antibodies

A

c. They kill virally infected cells by a perforin/granzyme dependent mechanism

Immunology Practice Questions Exam 1-3 (29 decks)

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