Antigens and Antigen Presentation

Question 1

most microbial antigens are ….

Answer 1

protein molecules

Question 2

what are microbes that replicate outside of the host cell

Answer 2

extracellular pathogens

Question 3

True or False:

most bacteria and parasites are extracellular

Answer 3

true

Question 4

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

Answer 4

intracellular pathogens

Question 5

what is an example of an intracellular pathogen

Answer 5

virus

Question 6

when are microbial antigens made

Answer 6

during microbial replication

Question 7

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

Answer 7

exogenous antigen

Question 8

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.

Answer 8

exogenous antigen - the microbe did not replicate inside

Question 9

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

Answer 9

endogenous antigen

Question 10

where do most bacteria live and replicate

Answer 10

outside of the cell

Question 11

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

Answer 11

true

Question 12

what does it mean to be ‘poorly immunogenic’

Answer 12

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

Question 13

what is the best type of viral vaccine to use

Answer 13

a live, non-encapsulated, attenuated vaccine

Question 14

what type of bacteria can readily replicate inside macrophages

Answer 14

facultative intracellular bacteria

Question 15

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

Answer 15

endogenous antigen

Question 16

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

Answer 16

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

Question 17

what are very small, obligate intracellular organisms

Answer 17

virus

Question 18

where do viral contents go once in the cell to replicate

Answer 18

cytosol

Question 19

what type of antigen is normally created with viruse

Answer 19

endogenous viral antigen

Question 20

what cells can kill virally infected host cells

Answer 20

natural killer cells
cytotoxic lymphocytes

Question 21

True or False:

Antibody if present can target extracellular virus

Answer 21

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

Question 22

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

Answer 22

non-microbial antigens

Question 23

what is another name for non-microbial antigens

Answer 23

cell surface antigens

Question 24

what are examples of cell surface antigens

Answer 24

blood group antigens
MHC molecules
CD molecules

Question 25

what are the nonmicrobial antigens of the blood group antigens

Answer 25

glycoproteins of glycolipids

Question 26

what are the nonmicrobial antigens of the MHC molecules

Answer 26

protein molecules expressed on the surface of all nucleated cells

Question 27

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

Answer 27

tissue recognition transplantation medicine

Question 28

what are CD molecules (cluster of differentiation)

Answer 28

surface molecules on immune cells used to define subsets of lymphocytes

Question 29

how are CD molecules identified

Answer 29

using monoclonal antibodies

Question 30

what are the main CD cells we are concerned with

Answer 30

CD 4 CD8 CD25

Question 31

where are CD4 cells found

Answer 31

T-cells with helper function

Question 32

where are CD8 cells found

Answer 32

T-cells that kill abnormal cells

Question 33

where is the CD25 molecule expressed

Answer 33

number of different cells

Question 34

what is the function of CD25

Answer 34

bind to IL-2

Question 35

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

Answer 35

dendritic cells macrophages B-cells

Question 36

where do the professional APCs present an extracellular antigen to

Answer 36

MHC-II molecules

Question 37

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

Answer 37

T-helper cells

Question 38

what do T-helper cells do

Answer 38

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

Question 39

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

Answer 39

antibody production through humoral immunity

Question 40

what APCs are responsible for presenting intracellular pathogens

Answer 40

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

Question 41

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

Answer 41

MHC-I

Question 42

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

Answer 42

CTLs (cytotoxic T-cells)

Question 43

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

Answer 43

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

Question 44

what is the function of APCs

Answer 44

process and present exogenous antigens

Question 45

where do APCs present their exogenous antigens to specifically

Answer 45

CD4+ T-helper cells

Question 46

what are the non-professional APCs

Answer 46

host infected cells and host tumor cells

Question 47

when can T-helper cells see antigen

Answer 47

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

Question 48

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

Answer 48

any nucleated cell because they all contain MHC-I complexes

Question 49

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

Answer 49

T-helper cells

Question 50

how do B-cells know what antigen to make

Answer 50

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