Immunity to Microorganisms Flashcards Preview

Immunology > Immunity to Microorganisms > Flashcards

Flashcards in Immunity to Microorganisms Deck (35):
1

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

antibody response, IgA for local, IgG for serum

2

How are microorganisms actually destroyed in most cases?

phagocytic cell

3

What are killed by cytotoxic T cells?

infected host cells

4

What two things does specific immunity act to enhance?

uptake of microorganisms by phagocytic cells, activity of phagocytic cells

5

Where is lysozyme present? What does it do?

tears, nasal secretions, saliva, enzymatically destroys cell walls

6

What cells innately recognize bacteria?

neutrophils and macrophages

7

How are bacteria broken down in macrophages?

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

8

What are spreading factors?

collagenase and elastases that breakdown tissues to allow bacterial spread

9

What does protein A do? What bacteria has it?

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

10

What is M protein?

antiphagocytic factor found in strep.

11

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

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

12

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

N. gonorrhea, c. albicans, worms
IgA, antimicrobial peptides

13

What microorganisms are cytoplasmic? What is the protective immunity?

viruses, chlamydia, protozoa
cytotoxic T cells, NK cells

14

What microorganisms are vesicular? What is the protective immunity?

mycobacteria, trypanosomes, cryptococcus neoformans
macrophages

15

Is Ab helpful in killing of facultative IC parasites?

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

16

How are macrophages activated?

Th1 response

17

How doe activated macrophages kill IC parasites?

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

18

What cells are the memory cells in CMI?

memory CD4+ T cells

19

Do activated macrophages have memory?

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

20

Can dead bacteria elicit CMI?

No, only live bacteria produce CMI

21

Describe Th1 cytokines and effects.

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

22

Describe Th2 cytokines and effects.

IL-4, IL-5
stimulate Ab production

23

What is the important role of IFNgamma?

activates macrophages

24

How do CD8+ cells lyse infected host cells?

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

25

Why are T cells critical for immunity to parasites?

needed for activation of macrophages, don't directly kill

26

What is the role of CTLs in immunity to parasites?

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

27

Why are granulomas formed in response to parasite?

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

28

How do eosinophils kill parasites?

release of major basic protein

29

Which antibody is most important against helminths?

IgE

30

How do parasites escape immune response? (4)

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

31

What is the importance of Ab in viral immunity?

prevent infections by neutralizing virus

32

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

IgA neutralization response

33

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

lipid-coated viruses

34

How do interferons act in antiviral immunity?

IFNgamma activates macrophages to kill virus-infected cells
IFNa and IFNb produced by macrophages induce reduced susceptibility of neighbors to viral infection

35

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

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