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D2 Summer > Microbio Week 5 Part 2 (Exam 2) > Flashcards

Microbio Week 5 Part 2 (Exam 2) Flashcards

1
Q

Selection of immature B cells occurs where?

A

Bone marrow

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2
Q

The selection of immature B cells in the bone marrow occurs in an _________________ manner

A

antigen-independent

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3
Q

What are the 2 checkpoints in the maturation of B cells?

A
  1. preBCR
  2. IgM

(both promote survival)

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4
Q

How is the BCR diversity generated in order to reach 1011?

A

Random recombination of gene segments and removal/addition of nucleotides.

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5
Q

What are the 2 critical steps involved in the maturation of pre-B and immature B cells in the bone marrow?

A

pre-BCR and IgM

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6
Q

Isotype switching is associated with…

A

Cytokines

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7
Q

Affinity maturation is associated with…

A

Point mutations

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8
Q

Hypervariable regions are associated with…

A

Antigen-binding site

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9
Q

Plasma cells are associated with…

A

Antibody secretion

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10
Q

Which of the following would likely lead to a decrease in CD4 cells only?

Defect in CD40 expression
Defect in IFNγ production
Defect in MHC Class I expression
Defect in RAG expression
Defect in MHC Class II expression

A

Defect in MHC Class II expression

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11
Q

Which of the following will lead to a decrease in B cells?

Defect in RAG expression
Defect in MHC Class II expression
Defect in IFNγ production
Defect in B7 expression
Defect in IL21 production

A

Defect in RAG expression

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12
Q

What does the expression of pre-BCR and signal from IgM in B cells promote?

A

Survival

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13
Q

T/F: Receptor editing only occurs for T cells

A

FALSE; it only occurs for B cells

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14
Q

Light chain recombination that results in change of Ig specificity

A

Receptor editing

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15
Q

Eliminate immature B cells that can bind with high affinity ubiquitous self antigens

A

Negative selection

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16
Q

What distinguished B cells from T cells?

A. BCR diversity is not achieved by random rearrangement
B. Selection of B cells depends on antigen recognition
C. Expression of pre-BCR in contrast to pre-TCR induces cell survival
D. Receptor editing only occurs for B cells
E. T cells recognize native proteins

A

D. Receptor editing only occurs for B cells

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17
Q

B cells vs T cells:

Types of antigens recognized

A

B cells = protein, lipid, polysaccharide, nucleic acid
T cells = protein

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18
Q

B cells vs T cells:

Antigen form

A

B cells = UNprocessed
T cells = processed

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19
Q

B cells vs T cells:

Positive selection

A

B cells = antigen INdependent
T cells = antigen dependent

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20
Q

B cells vs T cells:

Negative selection

A

Both are antigen dependent

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21
Q

B cells vs T cells:

Receptor editing

A

B cells = yes
T cells = no

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22
Q

B cells are activated by antigen recognition, which results in ________ ___________ and ___________

A

clonal expansion; differentiation

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23
Q

Where do plasma cells that produce high affinity Ig migrate to?

A

BM or mucosal tissues

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24
Q

How long do plasma cells that produce high affinity Ig survive for?

A

Years

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25
Q

T/F: Memory B cells secrete Ig

A

FALSE

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26
Q

How long do memory B cells survive for?

A

A liftetime

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27
Q

Where do memory B cells survive for a lifetime?

A

Mucosal tissues and blood

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28
Q

Describe the secondary antibody response in comparison to the primary antibody response

A

Quicker
Larger
IgG more abundant
High affinity

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29
Q

What allows for signal 2 and enhances B cell activation?

A

Engagement of CR2 or TLR

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30
Q

What are the 2 types of antibody responses?

A

T dependent
T independent

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31
Q

Which antibody response?

-Response to nonprotein antigen
-IgM
-Low affinity Ig

A

T independent

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32
Q

Which antibody response?

-Response to protein antigen
-Isotype switching
-High affinity Ig

A

T dependent

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33
Q

Small molecules that cannot elicit immune response by themselves, but do so after binding to larger proteins/cells

A

Haptens

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34
Q

Name common haptens

A

Penicillin, nickel, poison ivy

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35
Q

What do B cells process?

A

Antigens

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36
Q

B cells and T cells recognize different ___________ of the same protein

A

epitopes

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37
Q

What epitopes do B cells recognize?

A

Native conformational epitopes

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38
Q

What epitopes do T cells recognize?

A

Peptide fragments

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39
Q

What does the recognition of peptide presented by B cells induce? (2)

A

CD40L upregulation in T cells
Production of cytokines

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40
Q

Engagement of CD40 and cytokine receptor on B cells leads to their proliferation and differentiation in _______ cells

A

plasma

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41
Q

What 3 things happen in the germinal center?

A
  1. Isotype switching
  2. Affinity maturation
  3. Selection of high-affinity B cells
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42
Q

4 steps of germinal center reaction

A
  1. Activation of B cells + migration into germinal center
  2. B cell proliferation
  3. Somatic hypermutation + affinity maturation; isotype switching
  4. Exit of high affinity AB secreting cells + memory B cells
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43
Q

What is immunoglobulin isotype switching?

A

Change in constant region of heavy chain

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44
Q

What signal does isotype switching require?

A

CD40L signal from Tfh cells

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45
Q

What is the type of heavy chain isotype determined by?

A

Cytokines produced by Tfh cells (IgG or IgE) or tissues (IgA)

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46
Q

What does switch recombination bring VDJ exon next to?

A

A different C gene

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47
Q

In switch recombination, does specificity of the Ig change?

A

NO, it has the same V region

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48
Q

In switch recombination, does the C region change?

A

YES, it reflects the function of the Ig

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49
Q

Selection of B cells with high affinity antigen receptors

A

Affinity maturation

50
Q

High affinity B cells interact with follicular dendritic cells that display what 2 things?

What do these 2 things help do?

A

Antigen
Tfh

Promote survival via CD40-CD40L

51
Q

What Ig is produced in salivary glands?

52
Q

Name the effector functions of antibodies/immunoglobulins (7)

ON EXAM

A
  1. Neutralization of microbes and toxins
  2. Opsonization and phagocytosis of microbes
  3. AB dependent cellular cytotoxicity
  4. Lysis of microbes
  5. Phagocytosis of microbes opsonized w/ complement fragments
  6. Inflammation
  7. Complement activation
53
Q

What is the role of the variable region of an AB?

A

Neutralization

54
Q

What is the role of the constant region of an AB?

A

Elimination

55
Q

How does neutralization of microbes occur?

A

Binding molecules on microbes required for infecting cells that blocks colonization

56
Q

Which antibodies are the most effective at neutralizing microbes?

A

ABs w/ high affinity for antigens

57
Q

What does clustering of FcR require?

A

Recognition of multivalent antigen by Ig

58
Q

What FcR promotes phagocytosis of Ig-coated microbes by phagocytes?

A

FcgammaRI/IIA

59
Q

What FcR induces killing of Ig-coated infected cells by NK cells (ADCC)?

A

Fcgamma/RIIIA (CD16)

60
Q

What FcR induces degranulation of mast cells and basophils/eosinophils?

A

FcERI

(E = epsilon)

61
Q

What is required for antibody-mediated opsonization and phagocytosis? (2)

A
  1. Multivalent AB coated microbe
  2. FcR clustering
62
Q

What cells bind to IgG-coated cells via FcgammaRIII (CD16)?

63
Q

What kind of killing is FcERI involved in?

A

IgE- and eosinophil-mediated killing of helminths

64
Q

When killing helminths, FcERI binds to _____ portion of the IgE-coated ____________

A

Fc; helminth

65
Q

What does FcERI binding to the Fc portion of the IgE-coated helminth trigger?

A

Degranulation of toxic mediators that kill helminth

66
Q

What does IgE- and eosinophil-mediated killing of helminths NOT target?

A

Infected cells

67
Q

What other process is FcERI involved in?

A

FcE-mediated allergic disease

68
Q

What does this describe?

Mast cells/basophils are coated with IgE specific for allergens via their FcERI

A

FcE-mediated allergic disease

69
Q

Clustering of FcERI bound to IgE by multivalent allergen in FcE-mediated allergic disease triggers what to occur?

A

Degranulation

70
Q

When discovering the complement system, Jules Bordet demonstrated the presence of a _______ _____________ component in antiserum (alexin) that mediate bacteriolysis

A

heat sensitive

71
Q

“Activation of complement involves the ____________ ____________ of those proteins to generate __________ (Zymogens) with proteolytic activity

A

sequential proteolysis; enzymes

72
Q

What are plasma proteins activated by?

73
Q

What does complement activation result in?

A

Phagocytosis, inflammation, and destruction of microbes

74
Q

What is the most important step of early complement activation?

A

Cleavage of C3 by C3 convertase

75
Q

What is the net result of the cleavage of C3 by C3 convertase?

A

Coating of microbes with C3b

76
Q

What does the late step of complement activation result in?

A

Membrane attack complex (MAC)

77
Q

What does the membrane attack complex (MAC) consist of?

A

C5b
C6
C7
C8
Multiple C9s that form a pore

78
Q

Most microbes have evolved to be resistant to MAC-mediated lysis. Which microbe is susceptible due to its thin cell wall?

79
Q

What prevents complement fixation at the surface of mammalian cells?

A

Plasma + membrane proteins

80
Q

When regulating complement activation, what inhibits proteolytic activity of C1r and C1s by dissociating them from C1q?

81
Q

When regulating complement activation, what do CR1, DAF, Factor H, and MCP bind to?

82
Q

When regulating complement activation, what do CR1, DAF, and C4BP bind to?

83
Q

When regulating complement activation, what inactivates C3b/C4b attached to cell surface?

84
Q

When regulating complement activation, what inhibits MAC formation?

A

S protein
CD59

85
Q

Name the plasma proteins that prevent complement fixation at the surface of mammalian cells (5)

A

C1 INH
C4BP
Factor H
Factor I
S protein

86
Q

Name the membrane proteins that prevent complement fixation at the surface of mammalian cells (4)

A

CR1
DAF
MCP
CD59

87
Q

What is important for Neisseria infection?

88
Q

Name some functions of the complement system (4)

A
  1. Opsonization of microbes to induce phagocytosis
  2. Increase vascular permeability
  3. Increase extravasation of plasma proteins and monocyte/neutrophils
  4. Increase microbicidal
    activities

(2-4 are done by anaphylatoxins)

89
Q

Where can these forms of protective immunity be found extracellularly?

Antibodies
Complement
Phagocytosis
Neutralization

A

Interstitial spaces, blood, lymph

90
Q

Where can these forms of protective immunity be found extracellularly?

Antibodies (especially IgA)
Antimicrobial peptides

A

Epithelial surfaces

91
Q

Where can these forms of protective immunity be found intracellularly?

Cytotoxic T cells
NK cells

92
Q

Where can these forms of protective immunity be found intracellularly?

T cell and NK cell dependent macrophage activation

93
Q

What are the 3 mechanisms of innate immunity to extracellular bacteria?

A
  1. Complement activation
  2. Opsonization and phagocytosis
  3. Stimulation of inflammatory reactions via anaphylatoxin
94
Q

Humoral immunity eliminate microbes and neutralize their toxins via antibodies that recognize …? (2)

A
  1. Cell wall antigens
  2. Secreted and cell-associated toxins
95
Q

Igs induce __________ and _________ of microbes and complement activation

A

opsonization; phagocytosis

96
Q

Bacterial protein antigens processed by DC activate CD4 helper T cells for what 3 things?

A
  1. Production of IL-17 and neutrophil recruitment
  2. Production of IFNg and activation of macrophages
  3. B cell help
97
Q

Innate immunity involves what 2 particular cells?

A

Phagocytes
NK cells

98
Q

What is cell-mediated immunity crucial for?

A

Adaptive immunity to intracellular bacteria

99
Q

In adaptive immunity to intracellular bacteria, what do CD4 T cells differentiate into?

A

Th1 effectors via IL-12

100
Q

In adaptive immunity to intracellular bacteria, how are macrophages activated?

A

T cell signals (IFNgamma)

101
Q

Name an example of adaptive immunity to intracellular bacteria

A

Antibodies against TB

102
Q

Lysis of infected cells is done by…?

A

Cytotoxic CD8 cells

103
Q

What 2 cells phagocytose fungi for intracellular killing?

A

Neutrophils
Macrophages

104
Q

Which responses are protective during innate immunity to fungi?

105
Q

What can cause an increased risk for oral candidiasis or thrush?

A

Upper dentures
Dry mouth

106
Q

What do innate and adaptive immune responses block? What does this lead to?

A

Block infection
Leads to elimination of infected cells

107
Q

What 2 things does innate immunity have to respond to viruses?

A

IFNalpha
NK cell killing

108
Q

__________ neutralize viruses, activate complement, and lead to ______________ of viral particles

A

Antibodies; opsonization

109
Q

What cells kill viro-infected cells?

A

CD8 T cells

110
Q

What is the limitation for parasites/protozoa?

A

Weak innate immunity

111
Q

What 2 things are involved in adaptive immunity to protoza?

A
  1. Macrophage activation
  2. Cytotoxic T lymphocytes
112
Q

For adaptive immunity to protozoa, how do macrophages become activated?

A

By Th1 cell-derived cytokines

113
Q

For adaptive immunity to protozoa, what do cytotoxic T lymphocytes respond against?

A

Lytic protozoa (malaria)

114
Q

For adaptive immunity to helminths, what does the activation of Th2 cells result in?

A

Killing of the helminth

(NOT infected cells!)

115
Q

Describe the process of adaptive immunity to helminths, which results in killing of the helminth. (4)

A
  1. Production of IL-4 -> induces IgE
  2. Production of IL-5 -> stimulates eosinophils
  3. Release of major cationic protein + major basic protein
  4. Degranulation of eosinophils + killing of helminth
116
Q

What is a common evasion mechanism for bacteria, viruses, and parasites?

A

Antigenic variation

117
Q

What is responsible for influenza pandemics?

A

Reassortment of virus RNA genomes (antigenic shift)

118
Q

What does the most effective vaccine lead to?

A

Production of high-affinity neutralizing antibodies + memory cells

(lifelong immunity)

119
Q

What does the caries vaccine lead to enhanced levels of?

A

Antigen-specific secretory IgA

D2 Summer (37 decks)

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