Antigens and Antigen Presentation Flashcards

1
Q

most microbial antigens are ….

A

protein molecules

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2
Q

what are microbes that replicate outside of the host cell

A

extracellular pathogens

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3
Q

True or False:

most bacteria and parasites are extracellular

A

true

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4
Q

which pathogens exist outside a host cell prior to infecting it but need to be inside a cell to replicate

A

intracellular pathogens

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5
Q

what is an example of an intracellular pathogen

A

virus

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6
Q

when are microbial antigens made

A

during microbial replication

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7
Q

what type of antigen is made by the pathogen outside of any host cell

A

exogenous antigen

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8
Q

Is this exogenous or endogenous antigen:

the extracellular pathogen is engulfed by a phagocytic cell and killed inside the cell. The pathogen now presents the antigen.

A

exogenous antigen - the microbe did not replicate inside

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9
Q

what type of antigen is made by the intracellular pathogen inside a host cell

A

endogenous antigen

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10
Q

where do most bacteria live and replicate

A

outside of the cell

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11
Q

True or False:
capsules of some bacteria are usually poorly immunogenic

A

true

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12
Q

what does it mean to be ‘poorly immunogenic’

A

an antibody may not be able to bind to the microbe because it is ‘keeping it hidden’

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13
Q

what is the best type of viral vaccine to use

A

a live, non-encapsulated, attenuated vaccine

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14
Q

what type of bacteria can readily replicate inside macrophages

A

facultative intracellular bacteria

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15
Q

which is more difficult/ dangerous to deal with - exogenous antigen or endogenous antigen

A

endogenous antigen

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16
Q

if a cell with endogenous antigen is killed and then re-engulfed. what type of antigen will be presented in the new phagocyte

A

exogenous antigen - the antigen was made before being in the cell. It was not replicated in the final cell that pick up the antigen

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17
Q

what are very small, obligate intracellular organisms

A

virus

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18
Q

where do viral contents go once in the cell to replicate

A

cytosol

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19
Q

what type of antigen is normally created with viruse

A

endogenous viral antigen

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20
Q

what cells can kill virally infected host cells

A

natural killer cells
cytotoxic lymphocytes

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21
Q

True or False:

Antibody if present can target extracellular virus

A

true - important to remember for rabies and the importance of vaccination

22
Q

what are molecules expressed on the surface of normal cells that in another animal could stimulate an immune response

A

non-microbial antigens

23
Q

what is another name for non-microbial antigens

A

cell surface antigens

24
Q

what are examples of cell surface antigens

A

blood group antigens
MHC molecules
CD molecules

25
Q

what are the nonmicrobial antigens of the blood group antigens

A

glycoproteins of glycolipids

26
Q

what are the nonmicrobial antigens of the MHC molecules

A

protein molecules expressed on the surface of all nucleated cells

27
Q

what are the non-microbial antigens in the MHC important for

A

tissue recognition
transplantation medicine

28
Q

what are CD molecules (cluster of differentiation)

A

surface molecules on immune cells used to define subsets of lymphocytes

29
Q

how are CD molecules identified

A

using monoclonal antibodies

30
Q

what are the main CD cells we are concerned with

A

CD 4
CD8
CD25

31
Q

where are CD4 cells found

A

T-cells with helper function

32
Q

where are CD8 cells found

A

T-cells that kill abnormal cells

33
Q

where is the CD25 molecule expressed

A

number of different cells

34
Q

what is the function of CD25

A

bind to IL-2

35
Q

if there is an extracellular pathogen, which cells are used as APCs

A

dendritic cells
macrophages
B-cells

36
Q

where do the professional APCs present an extracellular antigen to

A

MHC-II molecules

37
Q

what cells are activated after the presentation of an extracellular pathogen to the MHC-II molecules

A

T-helper cells

38
Q

what do T-helper cells do

A

activate B-cells to produce antibodies and macrophages and CTLs to kill target

39
Q

what is the end result of an extracellular pathogen being presented to the MHC-II

A

antibody production through humoral immunity

40
Q

what APCs are responsible for presenting intracellular pathogens

A

none. intracellular virus has to be presented through MHC-I

41
Q

how do host infected cells/ tumor cells present their intracellular antigens

A

MHC-I

42
Q

what cells are responsible for recognizing the MHC-I antigen signals from the host cells/ tumor cells

A

CTLs (cytotoxic T-cells)

43
Q

what is the result of tumor cells/ infected host cells using MHC-I to activate the CTLs

A

activated CTLs and cell-mediated immunity
(ability to kill infected cells and tumor cells)

44
Q

what is the function of APCs

A

process and present exogenous antigens

45
Q

where do APCs present their exogenous antigens to specifically

A

CD4+ T-helper cells

46
Q

what are the non-professional APCs

A

host infected cells and host tumor cells

47
Q

when can T-helper cells see antigen

A

only if it is presented on the surface of an APC within the MHC-II molecules

48
Q

what type of cell can present endogenous antigen to MHC-1 molecules

A

any nucleated cell because they all contain MHC-I complexes

49
Q

what does a B-cell need help from in order to start antibody production

A

T-helper cells

50
Q

how do B-cells know what antigen to make

A

based on what antigen is presented to them through the T-helper cell