Adaptive Immune Response - Focus On T Cells

Question 1

What does the lymphoid progenitor cell give rise to?

Answer 1

Lymphoid cell

Question 2

What proportion of the peripheral white blood cells are lymphoid progenitor cells?

Answer 2

20-30%

Question 3

Is the lymphoid progenitor cells nucleus big or small?

Answer 3

Big

Question 4

What size are lymphoid progenitor cells?

Answer 4

6-10 microns

Question 5

What are the two types of cell that lymphoid progenitor cells can become?

Answer 5

Effector or memory cells

Question 6

Where do T cells mature?

Answer 6

Thymus

Question 7

What happens to the thymus in childhood?

Answer 7

Enlarges

Question 8

What happens to the thymus in puberty?

Answer 8

Atrophies (basically disappears)

Question 9

What proportion of T cells are alpha beta T cells?

Answer 9

90%

Question 10

What are the three subtypes of alpha beta T cells?

Answer 10

Helper T cells
Cytotoxic T cells
Regulatory T cells

Question 11

Why are helper T cells activated?

Answer 11

To secrete cytokines to help immune response or to become memory cells

Question 12

What CDs to helper T cells express?

Answer 12

CD4 and CD3

Question 13

What are the three subgroups of helper T cells?

Answer 13

Th1, Th2 and Th17

Question 14

What CDs do cytotoxic T cells express?

Answer 14

CD8 and CD3

Question 15

Why are cytotoxic T cells activated?

Answer 15

To kill infected targets or to become memory cells

Question 16

How do cytotoxic T cells kill?

Answer 16

Via the release of toxic contents of granules or through induction of apoptosis

Question 17

What CDs do regulatory T cells produce?

Answer 17

Mainly CD4+ but some CD8

Question 18

What can regulatory T cells do?

Answer 18

Affect immune responses by either supressing them or activating them through direct cell contact or the secretion of soluble factors (cytokines)

Question 19

What are the two main types of regulatory T cells?

Answer 19

Natural or inducible

Question 20

What do gamma delta T cells do?

Answer 20

Recognise lipid antigens through TCRs

Question 21

What type of molecule is the T cell receptor?

Answer 21

Dimeric

Question 22

How are the two molecules of the T cell receptor linked?

Answer 22

Covalently by a disulfide bond

Question 23

What parts are a T cell receptor made up of?

Answer 23

A variable and a constant immunoglobulin- like domain

Question 24

What are the antigen binding sites on T cell receptors associated with?

Answer 24

CD3

Question 25

How are alpha beta T cells restricted?

Answer 25

Through MHC I or MHCII

Question 26

What does the alpha chain in the alpha beta T cell receptors consist of?

Answer 26

Germline variable, joining and constant regions

Question 27

What does the beta chain in the alpha beta T cell receptors consist of?

Answer 27

Germline variable, diversity, joining and constant regions

Question 28

What is the total repertoire of possible alpha beta T cell receptors?

Answer 28

1017

Question 29

What is the total repertoire of possible gamma delta T cell receptors?

Answer 29

1019

Question 30

How much of the mucosal T cells are made up by gamma delta T cell receptors?

Answer 30

70%

Question 31

What are some gamma delta T cells restricted through?

Answer 31

CD1c

Question 32

What stress indicators do some gamma delta T cells recognise?

Answer 32

HSP and butyrophilin

Question 33

What are multi-histocompatibility complexes?

Answer 33

Surface expressed molecule which bind peptides derived from antigen and present to T cells

Question 34

What do MHCs encode for?

Answer 34

Human leukocyte antigens

Question 35

Where are MHC Is expressed?

Answer 35

All uncleared cells

Question 36

Where are MHC IIs expressed?

Answer 36

On professional antigen presenting cells

Question 37

What domains are MHCIS made up of?

Answer 37

Alpha 1-3 and beta2-microglobulin

Question 38

What domains are MHCIIS made up of?

Answer 38

Alpha 1 and 2 | Beta 1 and 2

Question 39

Give the 5 steps in the antigen processing and presentation to CD4 cells

Answer 39

1- Uptake of extracellular proteins into vesicular compartments of APC 2- processing of internalised proteins in endosomal/lysosomal vesicles 3- biosynthesis and transport of class ii MHC molecules to endosomes 4 - association of processed peptides with MHCII molecules in vesicle 5- expression of peptide MHCs complexes on the cell surface

Question 40

Give the steps in the antigen processing and presentation to CD8 cells

Answer 40

1- production of proteins in teh cytosol 2- proteolytic degradation of proteins 3- transport of peptides from cytosol to the ER 4- assembly of peptide- class I complex’s in the ER 5- surface expression of peptide -class I complexes

Question 41

Where are dendritic cells usually derived from?

Answer 41

Myeloid (but can be lymphoid as well)

Question 42

What happens when the dendritic cell is immature?

Answer 42

They capture the antigen and migrate to the lymphoid tissues where they mature and effectively present or show antigen to the T cells

Question 43

Give 4 subtypes of dendritic cells

Answer 43

Langerhans, interdigiting, plasmacytoid and follicular

Question 44

What is the only antigen presenting cell that can present to naive T cells ?

Answer 44

Dendritic cells

Question 45

Give the names of 5 tissue specific dendritic cells

Answer 45

Langerhans, interstitial, blood myeloid, plasmacytoid, blood monocytes

Question 46

Where would you find langerhans cells?

Answer 46

Skin

Question 47

Where would you find interstitial cells?

Answer 47

In the dermis

Question 48

Give the 3 types of other antigen presenting cells (nto tissue specific)

Answer 48

Macrophages B cells Endothelial (sometimes)

Question 49

What is the first signal in teh APC-Tcell interaction?

Answer 49

The T cell recognising the peptide using its Tcell receptor

Question 50

What is the second signal in teh APC-Tcell interaction?

Answer 50

The CD28 on the T cell and the CD80/86 on the APC also recognise each other

Question 51

What is the third signal in teh APC-Tcell interaction?

Answer 51

APC produces cytokines

Question 52

When the T cell enters the thymus , what happens if there is a productive TCR rearrangement?

Answer 52

It will go to see if it recognises self MHCs

Question 53

When the T cell enters the thymus , what happens if there is a non- productive TCR rearrangement?

Answer 53

Apoptosis

Question 54

What happens if the T cell doesnt recognise self MHC?

Answer 54

Apoptosis

Question 55

What happens if the T cell recognises self MHC?

Answer 55

It is positively selected for

Question 56

What happens if the TCR recognises self antigens?

Answer 56

Apoptosis

Question 57

If the TCR doesnt recognise self antigens what happens?

Answer 57

It moves into the cortico-medullary region and into the medulla

Question 58

What do CD4 T cells recognise on a MHCII?

Answer 58

A peptide in the binding groove

Question 59

What do T helper cells do?

Answer 59

Produce a cytokine profile which directs the immune response to a particular outcome

Question 60

What coreceptor do CD4 +Th1 cells express?

Answer 60

CD4

Question 61

What do CD4+Th1 help to do?

Answer 61

Activate the cellular immune response

Question 62

What do CD4+Th1 cells produce?

Answer 62

Gamma interferon

Question 63

What do CD4+Th1 cells activate?

Answer 63

Cytotoxic T cells

Question 64

What pathogens is the Th1 response effective against?

Answer 64

Intracellular infections, bacteria, Protozoa and viruses

Question 65

What do CD4+Th2 cells help to activate?

Answer 65

Humoral immune response

Question 66

What interleukins do CD4+Th1 cells produce?

Answer 66

4, 5, 13

Question 67

What immune cells do CD4+Th1 cells activate?

Answer 67

B cells to produce an antibody

Question 68

What do CD4+Th17 cells help to protect?

Answer 68

The gut mucosa

Question 69

What do CD4+Th17 cells recruit (and where to)?

Answer 69

Neutrophils to the site of infection

Question 70

What infections are the CD4+Th17 cells effective against?

Answer 70

Extracellular bacteria and fungi

Question 71

What response does CD4+Th17 cells promote?

Answer 71

Neutrophil mediated inflammation

Question 72

What coreceptors do CD4+Treg cells express?

Answer 72

CD4, CD35 and FoxP3

Question 73

What is the function of CD4+Treg cells?

Answer 73

Maintain immune tolerance and suppress immune responses

Question 74

What do CD4+Treg cells produce?

Answer 74

Anti-inflammatory cytokines IL10 and TGFbeta

Question 75

How do tregs affect the functions of CD4+ and CD8+ T cells?

Answer 75

Inhibit the effector functions

Question 76

What does TGF stand for?

Answer 76

Transforming growth factor

Question 77

What do CD8+ cytotoxic T cells do?

Answer 77

Eliminate intracellular infections

Question 78

What do CD8+ cytotoxic T cells produce?

Answer 78

IL2, TNFalpha and gamma IFN

Question 79

Which T cell has a role in anti tumour immunity and rejection of transplants?

Answer 79

CD8+ cytotoxic

Question 80

How do CD8+ cytotoxic T cells kill (4)?

Answer 80

Contact delivers lethal hit CCTL then detaches and targets another cell Releases cytolytic molecules from intracellular stores Triggers apoptosis in target cells

Question 81

How does perforin work?

Answer 81

Forms pores in target cell membranes which allows the entry of granzymes

Question 82

What are granzymes?

Answer 82

Serine-esterase proteases

Question 83

What do granzymes do?

Answer 83

Induce apoptosis

Question 84

What are the three types of granzymes?

Answer 84

A, B and C

Question 85

What do CTL cytolytic proteins act as?

Answer 85

A specific synapse between the CTL and target

Question 86

What do the CTL cytolytic proteins limit?

Answer 86

Any collateral damage

Question 87

What do caspases lead to?

Answer 87

Apoptosis

Question 88

Which granzyme can trigger an apoptotic pathway?

Answer 88

B

Question 89

What molecules ligates the Fasreceptor

Answer 89

FasL

Question 90

What do NKTcells express?

Answer 90

T cell markers and NK cell markers

Question 91

Give an example of the glycolipids NKTcells respond to

Answer 91

Alpha galactocyl ceramide

Question 92

What are NKTcells restricted through?

Answer 92

CD1d