cell mediated immunity

Question 1

what is the immune response mediated by

Answer 1

T lymphocytes

Question 2

where do lymphocytes migrate or derive from?

Answer 2

thymus

Question 3

what happens once the lymphocytes migrate to the thymus

Answer 3

the mature into T lymophocytes

Question 4

when lymphocytes mature into t lymphocytes where do they next migrate to

Answer 4

to the lymphoid tissues

Question 5

how do you tell the difference between T lymphocytes

Answer 5

each one expresses different surface proteins (known as the clusters of differentiation)

Question 6

what type of CD molecules do early T cells have

Answer 6

CD4 - CD8

Question 7

what main CD molecule do T helper cells present

Answer 7

CD4+

Question 8

what do T helper cells secrete

Answer 8

cytokines (acting as messenger molecules)

Question 9

what do cytokines stimulate

Answer 9

B cells and macrophages

Question 10

what stimulates proliferation and differentiation of T cells esp. CD8+ CTL

Answer 10

cytokines secreted from T helper cells

Question 11

are Th1 or Th2 cytokines anti-inflammatory or proinflammatory

Answer 11

Th1- proinflammatory
Th2 - anti-inflammatory

Question 12

what do Th1 cytokines trigger

Answer 12

cell mediated immunity and phagocyte dependant inflammation

Question 13

what do Th1 cytokines target

Answer 13

intracellular parasites

Question 14

what is the main Th1 cytokine

Answer 14

IFN-y

Question 15

what do Th2 cytokines inhibit

Answer 15

phagocytosis independent inflammation

Question 16

does Th2 increase or decrease with tumour presence

Answer 16

increase

Question 17

what type of CD molecule do cytotoxic T cells express

Answer 17

mainly CD8+

Question 18

how do cytotoxic T cells kill cells

Answer 18

with intracellular microbes which produce foreign antigens

Question 19

what happens once the cytotoxic T cells are activated

Answer 19

cytotoxic granules are released into the target - ensuring specific kills and reduces collateral damage

Question 20

what is perforins role in cytotoxic t cells killing cells

Answer 20

it builds pores in the membrane for entry

Question 21

what is Granzyme A’s role in cytotoxic t cells killing cells

Answer 21

activates ssDNA breaks, caspase independent apoptosis (programmed cell death)

Question 22

what is Granzyme B’s role in cytotoxic t cells killing cells

Answer 22

activates caspase cystine proteases to initiate caspase dependant apoptosis

Question 23

what is regulatory T cells role in the immune system

Answer 23

inhibits the immune response, to maintain homeostasis
has a role in preventing allergy and hypersensitivity
has a role in transplant tolerance

Question 24

what do natural killer T cells share surface markers with

Answer 24

immune NK cells and cell mediated T cells

Question 25

what type of CD molecules do natural killer T cells express

Answer 25

CD16+ (they recognise IgG coated pathogens

Question 26

what is natural killer T cells role in the immune response

Answer 26

- surveillance and clearance of tumour cell (by increasing stress induced ligands) - maintains self tolerance and regulates autoimmune diseases

Question 27

what is the role of CD3

Answer 27

co-aids in activating CD8+ and CD4+

Question 28

where are CD3 molecules found in high percentage

Answer 28

peripheral T cells

Question 29

where is the CD45 marker expressed

Answer 29

on almost all leucocytes

Question 30

what do CD45 molecules do

Answer 30

they activate and supress lymphocytes - and have a role in T cell maturation

Question 31

what are APC's

Answer 31

antigen presenting cells

Question 32

what do APC's do to aid the immune response

Answer 32

they capture and display antigens to activate T lymphocytes

Question 33

what is the first stage of APC's capture and display of antigens

Answer 33

1- bacterium is engulfed by phagocytosis into a dendric cell and is encased into a phagosome

Question 34

what is the second stage of APC's capture and display of antigens

Answer 34

lysosomes fuse with the phagosome and digest the bacteria

Question 35

what is the third stage of APC's capture and display of antigens

Answer 35

immunodominant epitopes are associated with MHC II and are presented on the cell surface

Question 36

what do APC's include

Answer 36

dendritic cells, macrophages, B cells

Question 37

what are costimulators

Answer 37

molecules on APC's that function together with antigens to activate T cells

Question 38

what does MHC stand for

Answer 38

major histocompatibility complex

Question 39

what is a MHC

Answer 39

a group of genes that code for cell surface histocompatibility antigens

Question 40

what do MHC's do

Answer 40

they help anchor the antigen on the external surface of the APC

Question 41

what is required for the activation of naïve T cells

Answer 41

the recognition of MHC

Question 42

where are class 1 MHC's expressed

Answer 42

on virtually all nucleated cells

Question 43

where are class 2 MHC's expressed

Answer 43

dendric cells, B cells and macrophages

Question 44

what does polygenic mean

Answer 44

has several different class 1 and class 2 genes with similar functions

Question 45

what does polymorphic mean

Answer 45

has multiple variants of each type within the whole population

Question 46

what are MCH's that can only be found in humans known as

Answer 46

HLA's (human leukocyte antigens)

Question 47

what are class 1 encoded by (in terms of HLA)

Answer 47

HLA-A, HLA-B, HLA-C

Question 48

what are class 2 encoded by (in terms of HLA)

Answer 48

HLA-DR, -DP and -DQ