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Immunology > Immunity to Microorganisms > Flashcards

Immunity to Microorganisms Flashcards

1
Q

What is the primary local adaptive immune response to bacteria? primary serum response?

A

antibody response, IgA for local, IgG for serum

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2
Q

How are microorganisms actually destroyed in most cases?

A

phagocytic cell

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3
Q

What are killed by cytotoxic T cells?

A

infected host cells

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4
Q

What two things does specific immunity act to enhance?

A

uptake of microorganisms by phagocytic cells, activity of phagocytic cells

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5
Q

Where is lysozyme present? What does it do?

A

tears, nasal secretions, saliva, enzymatically destroys cell walls

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6
Q

What cells innately recognize bacteria?

A

neutrophils and macrophages

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7
Q

How are bacteria broken down in macrophages?

A

NADPH-oxidase, has buildup of reactive oxygen species that breakdown bacteria

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8
Q

What are spreading factors?

A

collagenase and elastases that breakdown tissues to allow bacterial spread

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9
Q

What does protein A do? What bacteria has it?

A

binds to the Fc region of IgG and blocks opsonizing action of IgG since it can’t be recognized by immune cells now, s. aureus

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10
Q

What is M protein?

A

antiphagocytic factor found in strep.

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11
Q

How does Ab respond to virulence factors of bacteria? (5)

A
  1. prevent attachment to epithelim using secreted IgA
  2. trigger complement to increase opsonization or lysis
  3. bind antiphagocytic M protein or capsule
  4. neutralize toxin
  5. neutralize spreading factors
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12
Q

What microorganisms act on the epithelial surface? What is the protective immunity?

A

N. gonorrhea, c. albicans, worms

IgA, antimicrobial peptides

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13
Q

What microorganisms are cytoplasmic? What is the protective immunity?

A

viruses, chlamydia, protozoa

cytotoxic T cells, NK cells

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14
Q

What microorganisms are vesicular? What is the protective immunity?

A

mycobacteria, trypanosomes, cryptococcus neoformans

macrophages

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15
Q

Is Ab helpful in killing of facultative IC parasites?

A

No, they increase the rate of phagocytosis but don’t affect clearance

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16
Q

How are macrophages activated?

A

Th1 response

17
Q

How doe activated macrophages kill IC parasites?

A

non-specific killing from increased reactive oxygen and reactive nitrogen species in the macrophage

18
Q

What cells are the memory cells in CMI?

A

memory CD4+ T cells

19
Q

Do activated macrophages have memory?

A

No, they exist for a short time only and have non-specific killing

20
Q

Can dead bacteria elicit CMI?

A

No, only live bacteria produce CMI

21
Q

Describe Th1 cytokines and effects.

A

IL-2, IFNgamma
stimulates CMI, activates macrophages
activates B cells to produce opsonizing Ab

22
Q

Describe Th2 cytokines and effects.

A

IL-4, IL-5

stimulate Ab production

23
Q

What is the important role of IFNgamma?

A

activates macrophages

24
Q

How do CD8+ cells lyse infected host cells?

A

FasL of CTL binds Fas on infected cell, cytotoxins (perforin, granzymes, granulysin)

25
Q

Why are T cells critical for immunity to parasites?

A

needed for activation of macrophages, don’t directly kill

26
Q

What is the role of CTLs in immunity to parasites?

A

kill cells infected with parasite so pathogen is released and can be eaten by activated macrophage

27
Q

Why are granulomas formed in response to parasite?

A

wall parasite off from rest of the host because of release of fibroblast growth factor from activated macrophages

28
Q

How do eosinophils kill parasites?

A

release of major basic protein

29
Q

Which antibody is most important against helminths?

A

IgE

30
Q

How do parasites escape immune response? (4)

A

inaccessibility (hide in host cells, form cysts), avoid recognition by varying surface Ag expression, immunosuppression of host, survive inside macrophage

31
Q

What is the importance of Ab in viral immunity?

A

prevent infections by neutralizing virus

32
Q

What is the prime mediator of antiviral immunity in respiratory, GI or GU tracts?

A

IgA neutralization response

33
Q

What kind of viruses can be lysed by action of Ab and complement?

A

lipid-coated viruses

34
Q

How do interferons act in antiviral immunity?

A

IFNgamma activates macrophages to kill virus-infected cells

IFNa and IFNb produced by macrophages induce reduced susceptibility of neighbors to viral infection

35
Q

How do neighbor cells reduce susceptibility to virus in response to IFNa and IFNb?

A

produce protein kinases to degrade RNA viruses, increase MHC class I expression and Ag presentation so more macrophages can bind, induces resistance to viral replication in cells, activates NK cells

Immunology (18 decks)

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