Immune Responses Flashcards

1
Q

What is Complement?

A

System of interacting proteins that play a role in innate immunity & inflammation

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2
Q

What do Membrane attack complex (MAC) of complement do?

A

Defends against gram-negative bacteria

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3
Q

What is the Classic pathway of activation of complement?

A

IgG or IgM mediated

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4
Q

What is the Alternative pathway of activation of complement?

A

Microbe surface molecules

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5
Q

What is the Lectin pathway of activation of complement?

A

Mannose or other sugars on microbe surface

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6
Q

What is the function of C3b?

A

Opsonization

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7
Q

What is the function of C3a & C5a?

A

Anaphylaxis

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8
Q

What is the function of C5a?

A

Neutrophil chemotaxis

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9
Q

What is the function of C5b-9?

A

cytolysis by MAC

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10
Q

What are the two 1° opsonins in bacterial defense?

A

C3b & IgG

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11
Q

What does C3b help clear?

A

Immune complexes

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12
Q

What are the inhibitors of complement?

A

Decay-accelerating factor (DAF) & C1 esterase inhibitor help prevent complement activation on self cells

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13
Q

What is C1 esterase inhibitor deficiency?

A

Hereditary angioedema

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14
Q

What is CI w/ C1 esterase inhibitor deficiency?

A

ACE inhibitors

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15
Q

What is C3 deficiency?

A

Severe, recurrent pyogenic sinus & resp tract infections

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16
Q

What does C3 deficiency inc susceptibilty to?

A

Type III hypersensitivity reactions

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17
Q

What is C5-C9 deficiency?

A

Recurrent Neisseria bactermia

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18
Q

What is DAF (GPI anchored enzyme) deficiency?

A

Complement-med lysis of RBC’s & paroxysmal nocturnal hemoglobinuria (PNH)

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19
Q

Which cytokines are secreted by macrophages?

A
  • IL-1
  • IL-6
  • IL-8
  • IL-12
  • TNF-alpha
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20
Q

What is IL-1?

A

An endogenous pyrogen

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21
Q

What does IL-1 cause?

A

Fever & acute inflammation

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22
Q

What does IL-1 activate?

A

Endothelium to express adhesion molecules; induces chemokine secretion to recruit leukocytes

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23
Q

What is IL-6?

A

Endogenous pyrogen

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24
Q

What is IL-6 secreted by?

A

Macrophages & Th2 cells

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25
Q

What does IL-6 cause?

A

Fever & stim production of acute-phase proteins

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26
Q

What is IL-8?

A

Major chemotactic factor for neutrophils

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27
Q

What is IL-12?

A

Induces indifferentation of T cells into Th1 cells & activates NK cells

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28
Q

What is IL-12 secreted by?

A

Macrophages & B cells

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29
Q

What does TNF-alpha do?

A
  • Mediats septic shock
  • Activates endothelium
  • Causes leukocyte recruitment & vascular leak
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30
Q

Which cytokines are secreted by all T cells?

A

IL-2 & IL-3

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31
Q

What does IL-2 do?

A

Stim growth of helper, cytotoxic & regulatory T cells

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32
Q

What does IL-3 do?

A

Supports the growth & differntiation of bone marrow stem cells. Functions like GM-CSF

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33
Q

Which cytokines are secreted by Th1 cells?

A

Interferon-gamma

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34
Q

What does Interferon-gamma do?

A
  • Activates macrophages & Th1 cells
  • Suppresses Th2 cells
  • Has antiviral & antitumor properties
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35
Q

Which cytokines are secreted by Th2 cells?

A

IL-4, IL-5, IL-10

36
Q

What does IL-4 do?

A
  • Induces differentiation into Th2 cells
  • Promotes growth of B cells
  • Enhances class switching to IgE & IgG
37
Q

What does IL-5 do?

A
  • Promotes differentiation of B cells
  • Enhances class switching to IgA
  • Stim the growth & differentiation of eosinophils
38
Q

What does IL-10 do?

A
  • Modulates inflammatory response
  • Inhibits actions of activated T cells & Th1
39
Q

What is IL-10 secreted by?

A

Th2 cells & regulatory T cells

40
Q

What are interferons (alpha, gamma, ß)?

A

Proteins that place uninfected cells in an antiviral state

41
Q

What do interferons induce?

A

Production of a rionuclease that inhibits viral protein synthesis by degrading viral mRNA (but not host mRNA)

42
Q

How do interferons interfere w/ viruses?

A

Activates NK to kill virus-infected cells

43
Q

How do alpha & ß interferons interfere w/ viruses?

A

Inhibits viral protein synthesis

44
Q

How do gamma-interferons interfere w/ viruses?

A

Inc MHC I & II expression & Ag presentation in all cells

45
Q

All cells except ___ ___ have MHC I.

A

Mature RBCs

46
Q

What are the cell surface proteins for T cells?

A
  • TCR
  • CD3
  • CD28
47
Q

What does TCR bind to?

A

Ag-MHC complex

48
Q

What is CD3 assoc w/?

A

TCR for signal transduction

49
Q

What does CD28 bind to?

A

B7 on APC

50
Q

What are the cell surface proteins for Helper T cells?

A

CD4, CD40 ligand

51
Q

What is the cell surface for Cytotoxic T cells?

A

CD8

52
Q

What are the cell surface proteins for B cells?

A
  • Ig
  • CD19
  • CD20
  • CD21
  • CD40
  • MHC II
  • B7
53
Q

What does Ig bind?

A

Antigen

54
Q

What is CD21 a receptor for?

A

EBV

55
Q

What are the cell surface receptors for Macrophages?

A
  • CD14
  • CD40
  • MHC II
  • B7
  • Fc & C3b receptors (enhance phagocytosis)
56
Q

What are the cell surface receptors for NK cells?

A

CD16 & CD56

57
Q

What does CD16 bind?

A

Fc of IgG

58
Q

What is CD56?

A

Unique marker for NK

59
Q

What is Anergy?

A

Self-reactive T cells become nonreactive w/o costimulatory molecule. B cells also become anergic but tolerance is less complete than in T cells

60
Q

Which bacteria have Superantigens?

A

S. pyogenes & S. aureus

61
Q

What do Superantigens do?

A

Cross-link the ß region of the T-cell receptor to the MHC class II on APCs

62
Q

What can Superantigens activate?

A

Any T cell l/t massive release of cytokines

63
Q

Which bacteria contain endotoxins/lipopolysaccharides?

A

Gram-negative bacteria

64
Q

What do endotoxins/lipopolysaccaride do?

A

Direclty stim macrophages by binding to endotoxin receptor CD14; Th cells are not involved

65
Q

What are some mech for Ag variation?

A

DNA rearrangement & RNA segment reassortment

66
Q

What are some classic examples of bacteria Ag varation?

A
  • Salmonella (2 flagellar variants)
  • Borrelia (relapsing fever)
  • Neisseria gonorrheae (pilus protein)
67
Q

What is a classic example of virus Ag variation?

A

Influenza (major= shift, minor=drift)

68
Q

What is a classic example of parasite Ag variation?

A

Trypanosomes (programmed rearrangement)

69
Q

What are the means of acquisition in Passive immunity?

A

Receiving preformed Ab’s

70
Q

What are the means of acquisition in Active immunity?

A

Exposure to foreign Ag’s

71
Q

What is the onset of Passive immunity?

A

Rapid

72
Q

What is the onset of Active immunity?

A

Slow

73
Q

What is the duration of Passive immunity?

A

Short span of Ab’s (half-life=3 weeks)

74
Q

What is the duration of Active immunity?

A

Long-lasting protection (memory)

75
Q

What are examples of passive immunity?

A
  • IgA in breast milk
  • Antitoxin
  • Humanized monoclonal Ab
76
Q

What are examples of Active immunity?

A
  • Natural infection
  • Vaccines
  • Toxoid
77
Q

When are patients given preformed Ab’s (passive)?

A

After exposure to Tetanus toxin, Botulinium toxin, HBV or Rabies virus

78
Q

When can combined passive & immunizations be given?

A

Case of hepatitis B or rabies exposure

79
Q

What are vaccines used for?

A

Induce an active immune response (humoral &/or cellular) to specific pathogens

80
Q

What is a Live attenuated vaccine?

A

Mircoorganism loses its pathogenicity but retains capacity for transient growth w/in inoculated host

81
Q

What does live attenuated vaccine mainly induce?

A

Cellular response

82
Q

What are the Pros & Cons of a live attenuated vaccine?

A
  • Pros: induces strong, often life-long immunity
  • Cons: may revery to virulent from
83
Q

What are some examples of live attenuated vaccines?

A
  • Measles
  • Mumps
  • Polio (Sabin)
  • Rubella
  • Varicella
  • Yellow fever
84
Q

What are Inactivated or killed vaccines?

A

Pathogen is inactivated by heat or chemicals; maintaining epitope structure on surface Ag is important for immune response

85
Q

What is induced by inactivated or killed vaccine?

A

Humoral immunity

86
Q

What are the Pros & Cons of inactivated or killed vaccine?

A
  • Pros: stable & safer than live vaccines
  • Cons: weaker immune response; booster shots usually required
87
Q

What are some examples of inactivated or killed vaccine?

A
  • Cholera
  • Hepatitis A
  • Poli (Salk)
  • Rabies