2.2.7 T-cell mediated immunity

Question 1

The _____ cell is the most important in primary response

Answer 1

dendritic

Question 2

when T-cells leave the thymus what are they considered?

Answer 2

mature Naive

Question 3

______ have encountered antigen and are ready to act

Answer 3

Effector T-cells

Question 4

Which Effector T-cell deals with pathogens in the cytosol, and recognizes MHC1?

Answer 4

Cytotoxic CD8

Question 5

Which Effector T-cell deals with pathogens in macrophage vesicles, and recognizes MHC2

Answer 5

CD4 / THC1

Question 6

what is the effector activation of CD8? CD4?

Answer 6

CD8: apoptosis
CD4: cytokines

Question 7

can an alpha/beta t-cell bind without a MHC?

Answer 7

no!

Question 8

Class 1 molecules (HLA-A,B,C) are found on what cells?

Answer 8

all nucleated EXCEPT RBC!!

Question 9

where are class II molecules found?

Answer 9

APCs

Question 10

APCs express what MHC?

Answer 10

MHC1 and MHC2

Question 11

_____ are immature dendritic cells. What can they do and not do?

Answer 11

Langerhan’s cells
They CAN process, they CANT present antigens

Question 12

When a Langerhan cell reaches the lymph node it can transform to a ______ which can _____

Answer 12

mature dendrite, can present but NOT process

Question 13

Where do mature/naive cells travel/interact with antigen?

Answer 13

mature/naive cells leave thymus –> enter lymph node –> encounter antigen on dendrite

Question 14

what are the 2 ways naive T-cells can enter the lymph node?

Answer 14

1. High endothelial venules (HEV)
2. Lymphatics

Question 15

How do T-cells interact with endothelium cells in the blood?

Answer 15

via adhesion molecules

Question 16

where are adhesion molecules expressed? what are they called?

Answer 16

on both T-cells and endothelium cells
- LFA-1 on T-cell, ICA-1 on endothelium

Question 17

what happens once LFA-1 and ICAM-1 interact?

Answer 17

diapedesis, lymphocyte can enter lymph node

Question 18

If a TCR does recognize an antigen, there is a conformational change that causes what to happen?

Answer 18

LFA-1 to bind tighter to ICAM-1, prolongs cell-cell contact

Question 19

what are the 2 signals involved in the activation of T-cells?

Answer 19

1. MHC and TCR co-receptors
2. co-stimulators (B7 on APC, CD28 on T-cell)

Question 20

Costimulatory signal + specific signal = _____
Specific signal alone = _____
Costimulatory signal alone = ______

Answer 20

• Activated T-cell
• Anergic T-cell
• No effect

Question 21

If T-cell recognized self antigen, it would become what?

Answer 21

anergic

Question 22

once a T-cell becomes anergic can it ever revert back to normal?

Answer 22

NO

Question 23

If T-cell cant find the appropriate antigen in the Thymus, it does what?

Answer 23

leaves by efferent vessel

Question 24

Naive T-cells that encounter their antigen will become _____

Answer 24

effector T-cells or memory t-cells

Question 25

what is the role of IL-2 in T-cell activation?

Answer 25

- activated T-cells express high affinity IL-2 receptor (with gamma, beta and alpha) - Activated T-cell secretes IL-2 - IL2 binds to IL2 receptor and sends a signal to T-cell - this induces proliferation

Question 26

completed IL2 receptor with gamma, beta, and alpha is called what?

Answer 26

CD25

Question 27

cytokines can have what kinds of effects?

Answer 27

autocrine, paracrine, endocrine

Question 28

what kinds of effects can interleukins have?

Answer 28

Redundant (different ILs have same effect) Synergic Antagonistic

Question 29

What different subsets do CD4 T-cells have?

Answer 29

TH1, TH2

Question 30

what does CD4-TH1 play a role in?

Answer 30

cell mediated immune response

Question 31

what does CD4-TH2 play a role in?

Answer 31

providing cytokines to activate B-cells

Question 32

what types of cytokines are present in TH1?

Answer 32

IL2, gamma interferon

Question 33

what types of cytokines are present in TH1?

Answer 33

IL2, IFN-gamma

Question 34

what types of cytokines are present in TH2?

Answer 34

IL4, IL5, IL6, IL10, IL13

Question 35

TH1 interferons are inhibited by _____

Answer 35

TH2 interferons (IL4, IL10)

Question 36

TH2 interferons are inhibited by _____

Answer 36

TH1 interferons (IL12, gamma IF)

Question 37

TH1 responds to _____ pathogens while TH2 responds to _____ pathogens

Answer 37

1- Intracellular 2- Extracellular

Question 38

TGF-B results in what kind of cell?

Answer 38

T- regulatory cell that expresses FoxP3

Question 39

the 4th kind of T-cell is _____

Answer 39

Th17

Question 40

what are the 5 kinds of T-cells we need to know?

Answer 40

TH1, TH2, TFH, TH17, Treg

Question 41

TH2 and TFH cells both have which cytokine in common?

Answer 41

IL4

Question 42

what is the major difference between TH2 and THF cells?

Answer 42

- TH2 cells leave the lymph node as an effector cell -TFH cells go to B cell area

Question 43

How does TH1 cell work?

Answer 43

- TH1 cell + MHC II on macrophage - T-cell activates macrophage - t-cell releases gamma interferon, this further activates macrophage to kill intracellular bacteria

Question 44

how are tuberculoid and lepromatous leprosy different?

Answer 44

Tuberculoid: - LOW infectivity -granulomas and local inflammation normal t-cell responsiveness Lepromatous: - HIGH infectivity -disseminated infection, bone, cartilage, nerve damage - Hypergammaglobulinemia

Question 45

which 2 are the pro-inflammatory cytokines?

Answer 45

IFN-alpha, IL-2 along with IL6,IL8,IL12, IL17, IL1

Question 46

______ is known as a chemokine

Answer 46

IL8

Question 47

_____ may play a role in bone resorption

Answer 47

IL1

Question 48

Dendritic cells can activate naive CD8 cells via _______ as co-stimulatory signal

Answer 48

B7-CD28

Question 49

After Cd28 and B7 bind, activated CD8+ T-cells can produce ______

Answer 49

IL2s

Question 50

stimulation of naive CD8 T-cells by APC can result in ______

Answer 50

proliferation of cells and subsequent effector cells

Question 51

what is missing on CD8 effector cells?

Answer 51

B7 and CD28. No co-stimulatory factors are required

Question 52

what are the effector cells that CD8 T-cells secrete to cause apoptosis?

Answer 52

Perforin, Granzymes, and granulysin

Question 53

_______ is a protein CD8 uses to form a pore in the target membrane

Answer 53

Perforin

Question 54

how is perforin different from MAC?

Answer 54

causes a pore but doesn't cause cell lysis, pore allows proteins in (ex: granzyme)

Question 55

____ are serine proteases that CD8 use to drive a target cell into apoptosis

Answer 55

Granzyme

Question 56

Why not lyse a cell that is intracellularly infected?

Answer 56

if we lyse it, the bacteria would escape, we dont want that

Question 57

_____ cells also use Perforin and release granozymes. The difference is that this cell has a non-specific function

Answer 57

NK

Question 58

once the CD8+ T-cell destroys a target, can it kill another cell?

Answer 58

Yes! it can regenerate granules and kill more cells

Question 59

Summary: what cytokines do TH1, TH2, TFH, TH17 and Treg produce?

Answer 59

TH1: IFN-gamma, IL2 TH2: IL4, IL-10, IL-13, IL-6 TFH: IL4, IL6 TH17: IL-17 Treg: TGF-B, IL-10