1.4.2 Immune Responses to Viruses I Flashcards

1
Q

What are the 3 general mechanisms by which the immune system controls or eliminates viruses?

A
  1. Soluble extracellular factors that:
    • Damage viral structures
    • Inhibit virus binding to, entry into or un-coating in host cells
    • Promote clearance, uptake and elimination by phagocytic cells
  2. Inhibition of intracellular virus replication by:
  3. Immune-mediated recognition and lysis of virus-infected host cells by NK cells and CTL
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2
Q

Describe the role of interferons, complement and NK cells in antiviral immunity.

A
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3
Q
A

A, D, E

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4
Q

What are the 3 ways that innate immune cells recognize viruses?

A

Cell surface PRR

Endosomal PRR: Toll-like receptors

Cytosolic PRR: Nod-like receptors

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5
Q

What are the main roles of interferons (5)

A
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6
Q

What are the important facts about complement?

A

All 3 pathways of complement recognize patterns at some level

All pathways lead to the production of a C3 Convertase

C3b/iC3b acts a potent opsonin

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7
Q

What are the 3 ways that complement disrupts the pathogenesis of viruses?

A
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8
Q

What is the role of NK cells in innate immunity?

A

Kill, Kill, Kill everything that doesn’t express MHC class I

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9
Q

Describe 3 major protective mechanisms of immune protection against viruses provided by the adaptive immune system. Explain the role of antibody, CTL and Th cells.

A
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13
Q

What is the role of Th cells?

A
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14
Q

What is the role of Cytotoxic T cells in adaptive immunity?

A
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15
Q
A

C

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16
Q

What are some of the host innate/adaptive techniques to fight off viruses?

A
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17
Q

What some ways that viruses try to evade the immune system?

A
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21
Q
A
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22
Q
A

B. Inhibition of MHC Class I expression

23
Q
A

B. Antigenic variation

26
Q

Which type of Ig is more effective at mucosal surfaces in preventing host cell attachement to epithelium?

A

IgA

27
Q

What Ig is important in facilitating clearnace from infected tissues -> opsonophagocytosis?

A

IgG > IgM

28
Q

What is seroconversion? How can it be important in diagnosis?

A

A rise in serum Ab titers.

IgM implies a recent, primary infection

IgG implies either a more chronic or repeat infection

34
Q

What what might the recurrence of infection by a virus that had previously gone latent?

A

Cellular immune defects exist

35
Q

What are some ways that viruses try to alter MHC expression and Ag presentation?

A
  1. Disrupts peptide transport and loading of MHC I
  2. Degradation of MHC I
  3. Binds MHC class II and prevents peptide loading
36
Q

What some mechanisms that viruses employ to alter cytokines/growth factors?

A
  1. produce immunosuppressive IL-10-like mimic
  2. encode soluble receptors
  3. encode EGF-like mimic that promotes epithelial cell growth and viral replication
40
Q

What are some of the pathogen immune evasion mechanisms that evade the important host protective mechanisms?

A

Persistance (waiting for immunosuppression), antigenic variation, decreased MHC-I, immune suppression

41
Q

What are the 3 general immune mechanisms for eliminating viruses that involve innate and adaptive immunity?

A

Innate: complement, interferon, NK cells

Adaptive: Ab (neutralizing clearance, ADCC) and CTLs

42
Q

More cards need to be made using the supplemental materials!

A