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► Med Misc 19 > "Microbiology/Immunology Immunity to Microorganisms" SANA > Flashcards

"Microbiology/Immunology Immunity to Microorganisms" SANA Flashcards

1
Q

If you add antibody to CTLA 4, what would happen?

A

I would not be able to inhibit T-cell activity, and T-cell activity would stay up.

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2
Q

If you block all B7 in the body, what would happen?

A

You would not be able to stimulate any T-cells.

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3
Q

Name two chemical defenses against microorganisms the skin has.

A

Fatty acids and antimicrobial peptides.

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4
Q

How do cilia and surfactants in the lung help defend us against microorganisms?

A

They move bacteria and other pathogens out of our system.

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5
Q

Most bacteria die inside a _______

A

Phagocyte

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6
Q

What is the common function of the following receptors on macrophages:
mannose receptor, Toll-like receptors, lipopolysaccharide receptors, scavenger receptor

A

They are part of the innate immunity that recognize bacteria and phagocytize it.

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7
Q

Once phagocytizes, the bacteria are killed through a critical component of the internal reaction involving _______

A

Reactive oxygen species.

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8
Q

Which of the following is not a virulence factor of extracellular pathogens:

a. ability to survive acid environments
b. producing spreading factors
c. producing toxins
d. ability to lyse neutrophils
e. all of the above are virulence factors.

A

e

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9
Q

Why are some bacteria left behind in the respiratory tract even after the tract is flushed out?

A

Some bacteria have the ability to adhere to the epithelium and stay there.

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10
Q

The primary adaptive immune response to bacteria is _______

A

antibody

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11
Q

Why are some bacterial capsules, such as the ones found on S. pneumonia, considered virulence factors?

A

They are anti-phagocytic capsules that protect the bacteria

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12
Q

Why is Protein A, found in the S. Aureus bacteria considered a virulence factor?

A

It blocks the opsonizing actions of IgG

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13
Q

True or False? Antibody kills bacteria

A

False, antibody does NOT kill bacteria. It acts to neutralize, opsonize, trigger complement among other things.

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14
Q

What is the function of IgA secreted by antibody?

A

Prevent attachment of bacteria to epithelium, allowing them to be flushed away.

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15
Q

How does antibody increase opsonization or lyses?

A

By triggering complement

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16
Q

True or false? Opsonized bacteria are taken up and killed slower?

A

False: opsonizes bacteria are taken up and killed faster than non-opsonized bacteria.

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17
Q

Which of the following are NOT functions of the antibody?

a. neutralize toxins and spreading factors
b. trigger complement
c. secrete IgA to prevent attachment to epithelium
d. bind to antiphagocytotic proteins and capsules to opsonize
e. directly kill bacteria

A

e

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18
Q

What is the difference between toxins and toxoid?

A

A toxin has the ability to harm the host, while a toxoid is an inactivated toxin, which cannot harm us. A toxin is both toxic and immunogenic while a toxoid is no longer toxic but is immunogenic.

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19
Q

Which receptor does the bacteria coated with antibody (being opsonized) bind to when being phagocytosed?

A

The Fc receptor.

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20
Q

True/false? can an antibody direct a natural killer cell to kill?

A

true

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21
Q

Antibodies are very important is the killing of ___________ (intracellular/extracellular) bacteria.

A

Extracellular

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22
Q

Which of the following is true of Listeria monocytogenes, Mycobacterium tuberculosis, and Mycobacterium leprae?

a. They are all facultative intracellular pathogens
b. They are all extracellular pathogens

A

a.

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23
Q

What is a facultative intracellular parasites?

A

These organisms can grow inside a cell (phagosome) as well as outside.

24
Q

Name two ways in which facultative intracellular parasites can survive the phagosome.

A

Preventing fusion of the lysosomes with the phagosomes and surviving digestive enzymes of the phagolysosome.

25
Q

You perform an experiment injecting mice with low and high doses of listeria. Mice that were injected with high doses after being initially injected with low doses a month earlier survived. Why?

A

The low dose did not kill the mice and instead activated macrophages and long-term specific immunity through the CD4+ memory T-cells. The listeria from the high dose a month later were identified and immediately destroyed.

26
Q

True or false. Antibody increases both the rate of phagocytosis and killing.

A

False. Antibody only increases the rate of phagocytosis and not the killing.

27
Q

Activated macrophages are involved in __________ killing while CD4+ T-cells induce ________ immunity.

a. specific
b. non-specific

A

b; a

Activated macrophages are involved in non-specific killing while CD4+ T-cells induce specific immunity.

28
Q

The cells that transfer specific immunity are ________

A

CD4+ T-cells

29
Q

Immunity can be transferred from one animal to another through:

a. cells not serum
b. through serum not cells
c. through antibody transfers

A

a.

30
Q

What happens if listeria is not killed fast enough in the macrophage?

A

It escapes from the phagosome of the macrophages into the cytoplasm, dividing and moving to other cells

31
Q

What are activated macrophages?

A

Activated macrophages are found in the sites of prior infections and can kill many intracellular parasites (non-specific) as they have heightened ability due to more enzymes etc.

32
Q

In your experiment injecting listeria into mice, you notice that the sites where you have injected low doses are populated with several macrophages. What will happen when you introduce these macrophages to new listeria?

A

They will be able to kill the listeria immediately.

33
Q

True or false? Immunity is cell-mediated.

A

True

34
Q

Long-term immunity is ________

a. specific
b. non-specific.

A

specific

35
Q

Which of the following induce cell mediated immunity?

a. live bacteria
b. dead bacteria

A

a

36
Q

Which of the following induce antibodies?

a. live bacteria
b. dead bacteria

A

b

37
Q

What are the two types of helper T-cells?

A

TH1 and TH2

38
Q

Which of the following types of helper T-cells stimulate cell-mediated immunity and which of the following mediate antibody production?

a. TH1
b. TH2

A

TH1: cell-mediated immunity
TH2: antibody production

39
Q

On a culture with macrophages, you add IFN-y. What will happen to the macrophages?

A

They will become activated since TH1 produces INF-y, and is a result of cell-mediated immune response leading to macrophage activation.

40
Q

Which type of helper T-cell is responsible for IL-4, IL-5 and general B-cell activation?

A

TH2

41
Q

While tuberculoid leprosy lesions express a TH1 helper T-cell response, lepromatous leprosy lesions express a TH2 response. What difference do you express in the ways the body responds to the two?

A

Because tuberculoid leprosy has a TH1 response, macrophages are activated, with normal T-cell response against specific antigen, leading to low infectivity, low damage and low inflammation. Because lepromatous leprosy shows TH2 response, it will make copious amounts of antibodies, but will not be specific and disseminated infection with high infectivity will occur.

42
Q

Which of the following is not a function of activated T-cells?

a. activate macrophages
b. kill infected macrophages, releasing bacteria to be destroyed.
c. induce T-cell proliferation
d. induce macrophage differentiation
e. produce antibodies
f. induce macrophage adhesion and accumulation

A

e

43
Q

What is the function of TH2 cells?

A

activate B-cells to produce antibodies.

44
Q

In listeria, when the organisms is in the cytoplasm, which MHC class would the antigens be presented to?

A 
MHC Class I (cytoplasmic antigens)
 (while MHC class II antigens come from phagosomes).
45
Q

Name the cytokines released by TH2 that help activate B-cells.

A

IL4, 5, 6

46
Q

Which cells are required to kill infected macrophages?

A

CD8+ cells

47
Q

True or false? Will you be able to kill pathogens without activated macrophages?

A

False, activated macrophages are needed to kill better.

48
Q

Parasites are _______

a. intracellular
b. extracellular

A

intracellular (mostly)

49
Q

Why are CD8+ cells not able to directly kill parasite/bacterial pathogen?

A

CD8+ cells recognize antigens only in the context of self MHC class I (a bacteria or pathogen will never have self- MHC class I). Thus we need activated macrophages.

50
Q

Without T-cells, you’re main problem is infection with _______

a. bacteria
b. viruses
c. multicellular parasite

A

b

51
Q

Are activated macrophages able to kill certain infected cells?

A

Yes

52
Q

Which cytokine secreted from CD4 T-cell and/or CD8 T-cell itself will lead to the proliferation of the CD8 T-cell?

A

IL-2

53
Q

Can the cytotoxic CD8 cell move around after targeting cells?

A

Yes, it can go from cell to cell.

54
Q

What is a major difficulty in making an HIV vaccine?

A

It will require mediating cell-mediated immunity, and that’s much more difficult than the antibody vaccines.

55
Q

What are the 3 functions of the IFN-alpha and INF-beta produced by virus infected cells?

A
  1. they induce resistance in other cells
  2. increase MHC class I expression and antigen presentation.
  3. activate NK cells.

► Med Misc 19 (32 decks)

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