Differentiation And Functions Of CD4+ T Cells Flashcards Preview

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Flashcards in Differentiation And Functions Of CD4+ T Cells Deck (79):
1

Alpha beta TCRs recognize and bind to __.

Peptides presented within the MHC molecules and MHC itself.

These cells also express either CD4 or CD8 co-receptors.

2

Where does activation of T cells occur?

In the lymph nodes.

3

What are langerhans cells?

Immature dendritic cells which do not express high levels of B7.

They stimulate naive T cells.

4

What does Ag recognition involve?

Clustering of TCRs.

5

What is the activation of T cells initiated by?

A signaling cascade after TCRs recognize specific Ag.

6

What is needed to activate a T cell?

TCR, CD4 or CD8 and CD3.

CD4 for T helper cells

CD8 for CTLs

7

When the TCR is engaged and activates T cells, the T cell must:

Receive a co-stimulatory signal.

8

____ can be considered as an "amplifier" that improves signaling of T cells.

Co-stimulation.

This involves B7 and CD28.

With co-stimulation, 100 fold fewer of clustered TCRs are needed for activation.

9

Once T cells are Ag-activated, what do they produce?

IL-2 and IL-2R, which leads to cell proliferation.

The result is the expansion of the clone of T cells that are specific for the Ag.

10

What do T cells differentiate into?

Effector cells or memory cells.

11

What drives proliferation of T cells, and is also called the "T cell growth factor"?

IL-2

12

True or false: naive T cells do not have IL-2 receptor (IL-2R) expressed on their surface.

True

13

True or false: activted T cells produce a large amount of IL-2 and express IL-2R.

True

14

___ enhances resistance of activated T cells to apoptosis.

IL-2

15

How do effector T cells migrate through blood vessels in peripheral tissues?

They bind to endothelial cells that have been activated by cytokines produced in response to infection in these tissues.

16

CD4+ cells recruit and activate phagocytes. What do the phagocytes destroy?

Microbes

17

What do CD8+ lymphocytes kill?

Infected cells

18

True or false: each subset of T helper clls tends to oproduce a set of particular cytokines.

True

19

What do Th1 cells activate?

A cell-mediated immune response.

20

What do Th2 cells activate?

An Ab-mediated immune response.

21

What are Th17 cells involved in?

Inflammation and anti-bacterial response.

22

Why are PRRs important for innate and adaptive immunity?

Pathogen recognition by immature DCs through PRRs is an important bridge between innate and adaptive immunity.

23

What is the result of PRR signaling?

Activation and maturation of antigen-presenting cells (APCs)

24

APC processed antigen is presented to what cells?

Naive Th0 cells.

25

Secreted IL-12 assists the development and differentiation of what type of helper cell?

Th1 cell

26

What are four main classes of CD4+ cells?

Treg

Th1

Th2

Th17

27

What causes differentiation of Treg cells?

IL-2 + TGF beta

28

What are the functions of Treg cells?

Suppresses tumor immunity

Promotes immune tolerance

Maintains lymphocyte homeostasis

29

What cytokine activates Th1?

IL-12

30

What are the functions of Th1?

Promotes tumor immunity

Intracellular pathogens

Drives autoimmunity

31

What acitvates Th2?

IL-4

32

What are the functions of Th2?

Extracellular pathogens

Allergy

Asthma

33

What activates Th17?

TGF-beta

IL-6

IL-21

34

What are the functions of Th17?

Tumor immunity

Breaks immune tolerance

Extracellular bacteria

Autoimmunity

35

What immune reactions are stimulated by Th1 cells?

Macrophage activation

IgG production

36

What immune reaction is associated with Th2?

Mast cell, eosinophil activation,

IgE production

Alternative macrophage activation

37

What immune reactions are associated with Th17?

Neutrophilic

Monocytic inflammation

38

What is the host defense associated with Th1 cells?

Intracellular microbes

39

What is the host defense associated with Th2 cells?

Helminthic parasites

40

What is the host defense associated with Th17?

Extracellular bacteria; fungi

41

What is the function of TGF-beta?

It functions mainly as an inhibitor of immune responses

42

What is involved in the development of a Th1 cell?

IL-12 and IFN-gamma activate a T cell.

T-bet, STAT4 and STAT1 activate a Th1 cell

43

What is involved in the development of a Th2 cell?

IL-4 activates a T cell.

GATA-3 and STAT6 activate a Th2 cell

44

What is involved in the development of a Th17 cell?

A dendritic cell uses IL-1, IL-6, IL-23 and TGF-beta to activate a T cll.

ROR gamma t and STAT3 activate a Th17 cell.

45

What is IL-12 produced by?

DC and macrophages.

46

In the development of Th1 cells, what produces IFN-gamma?

NK cells

47

What is the function of IFN gamma in the development of Th1 cells?

It amplifies the Th1 repsonse and inhibits the development of Th2 and Th17 cells.

48

In the development of Th2 cells, what produces IL-4?

Activated T cells or by mast cells and eosinophils.

These activate GATA-3 and STAT6, which stimulate the differentiation of naive CD4+ T cells to the Th2 subset.

49

What is the function of IL-4 during the development of Th2 cells?

It amplifies the response (development of Th2 cells) and inhibits the development of Th1 and Th17 cells.

50

What transcription factors are activated by IL-1, IL-6 and TGF beta?

ROR gamma t and STAT3.

These stimulate the differentiation of Th17 subset.

51

What do ROR gamma t and STAT3 regulate the production of?

IL-21. This amplifies generation of Th17 cells.

52

What cytokine is very important in the differentiation of Th17 cells?

IL-23

53

What is the function of IL-17?

It protects from extracellular pathogens and is involved in tissue inflammation and autoimmunity.

54

How does TGF-beta promote the Th17 response?

By suppressing Th1 and TH2 cells, both of which inhibit the Th17 differentiation.

55

What is the role of oxygen species, nitric oxide, and increased lysosomal enzymes in cell-mediated immunity?

Killing of microbes in phagolysosomes

56

What is the role of the secretion of cytokines and chemokines in cell-mediated immunity?

Leukocyte recruitment

Th1 differentiation, IFN gamma production

57

What is the role of increased expression of B7 costimulators and MHC molecules?

Increased T cell activation (amplification of T cell response).

58

What are functions of Th2 cells?

Mast cell degranulation

Intestinal mucus secretion and peristalsis

Eosinophil activation

Alternative macrophage activation (tissue repair)

59

What is the funciton of ROS, NO and l ysosomal enzymes?

Phagocytosis and killing of many bacteria and fungi.

60

What is the role of chemokines (IL-1, IL-12, IL-23)?

Inflammation

61

What are the roles of IL-10 and TGF beta?

Anti-inflammtory effects, wound repair and fibrosis

62

What are the functions of Th17 cells?

Inflammation, neutrophil response

Increased barrier function

63

True or false: CD8+ T cells are activated by mechanisms that involve cross presentation of antigens to CD8+ T cells.

True

64

Where are CD8+ T cells activated?

In the LN by dendritic cells loaded with Ags exactly as CD4+ T cells are.

65

True or false: CD4+ helper T cells produce cytokines that stimulate CTL differentiation.

True

66

True or false: CD4+ helper T cells enhance the ability of APCs to stimulate CTL differentiation.

True

67

True or false: CD8+ T cells recognize antigen + costimulators on professional APCs, which results in CTL differentiation without helper T cells.

True

68

CTLs are activated to release their granule contents. What are in the granules?

Perforin and granzyme

69

What do CD8+ T lymphocytes secrete, and what does it activate?

They secrete IFN-gamma, which activates macrophages.

70

What do nontraditional gamma delta T cells have?

Gamma delta TCRs and CD3.

Most of them do not express CD4 or CD8 co-receptors.

71

Where are nontraditional gamma delta T cells most abundant in?

The intestine, uterus and the tongue

72

What are the functions of gamma detla T cells?

First line of defense

Regulatory cell

Bridging between innate and adaptive responses

73

Gamma delta T cells are considered a component of what type of immunity?

Adaptive immunity.

74

Rearrangement of TCR genes produces __.

Junctional diversity.

75

True or false: NKT cells share properties and CD markers of both T cells and NK cells.

True

76

What do NKT cells recognize?

Self- and foreign lipids and glycolipids.

77

What is the role of activated NKT cells?

They produce large quantities of IFN-gamma, IL-4 and GM-CSF, as well as other cytokines and chemokines. They also rapidly release cytokines. They also promote or suppress different immune responses.

78

What occurs when there is a dysfunction or deficiency of NKT cells?

Autoimmunity (diabetes or atherosclerosis)

Cancers

Progression of asthma.

79

Over 90 - 95% of T cells in the circulation have ___.

Alpha beta TCRs.