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Flashcards in T cell Robinson Deck (95):
1

Gamma Delta T cells

MHC type system that recognizes lipid rich antigens
-important for host/environment interfaces
-produce several early cytokines like 1, 6

2

Gamma Delta T cells

MHC type system that recognizes lipid rich antigens
-important for host/environment interfaces

3

What are T cells responses regulated by?

specific cytokines and Tregs

4

What type of antigen conformations do antibodies recognize?

3D

5

What type of antigen conformations do t-cells recognize?

peptides in the context of MHC

6

If an antigen is prestented by an MHC2 to a niave CD4 Tcell what 4 responses could occur?

Th1, Th2, Th17, Treg

7

If an antigen is presented by an MHC2 to a naive CD4 T Cell what 4 responses could occur?

Th1, Th2, Th17, Treg
-commitment to a subset depends on host genetics, type of infection, and which type of TLR and cytokine profile

8

Th1

enhances and amplifies cellular mediated immunity by activating macrophages/ and or promoting cytotoxic responses by CD8

9

Th2

promotes optimal antibody production

10

Th17

chronic inflammation

11

Treg

modulates or suppresses immune responses

12

T-FH

high affinity antibody production in the germinal center of a lymph node

13

What does commitment to a subset depend on?

which TLR system is activated and which cytokine profile becomes dominant at the time of presentation

14

Where do activation steps of the various cd4 cells occur?

following initiation-activation steps occur in the secondary lymphoid tissues

15

How many chain peptides are on a cytokine?

2 usually encoded by separate genes

16

What 2 things do all cytokines exhibit?

pleiotropism and redundancy

-at concentrations similar to hormones

17

What do lymphocytes and macrophages use cytokines for?

to regulate the intensity of an immune response

18

Do most cell/cytokine systems have agonist/antagonist dynamics?

yes

19

Can cytokines actions vary and depend on the state of the target cell?

yes

20

What provokes the classic Th1 response?

Infections by organisms that require phagocytosis and intracellular killing

21

What is the obligatory Th1 helper initiator cytokine?

12

22

What is the obligatory Th1 helper initiator cytokine?

12(also has a potent effect on NK cells)

23

What co-stimulatory molecules do Th1 cells upregulate when activated?

CD 28 and CD 154 (40L)

REQUIRED DETERMINANT

24

What cytokines does Th1 provide to propagate the TMMI response?

IL-2 and INF gamma

25

What 3 things is INF gamma produced by?

1. Th1(CD4)
2. NK
3. activated CD8 cells

26

What 3 things does INF gamma do?

-activator of macrophages
-upregulated of MHC2 and endothelial receptors
-suppressor of Th2 and Th17

27

What does Il21 do and what produces it, what 2 circumstances does it exist?

Th1 cells produce IL 21-
potent promoter of CD8 killing acitivity

in absence of INF gamma it is a potent promoter of B cell growth and development

28

What is IL 2 produced by?

Th1 and CD8

29

What strongly depends on IL2?

Tregs

30

What does IL 2 do?

-critical growth cytokine
-acts in autocrine and paracrine needs
-IL2R expressed as a functional unit after antigen activation
-genetic defects in its assembly result in severe immune deficiency disease

31

What has Th1 helper activation developed to provide?

an antigen specific way to recruit highly activated macrophages

32

Can small numbers of Th1 recruit vast numbers of macrophages?

yes

33

The end result of TMMi is activated macrophage, what does the macrophage produce? What do these cytokines do?

-Tetrad
1, 6, 8, and TNF alpha

-wide range of autocrine and paracrine and systemic effects that promote inflammation

34

What does pro-inflammatory IL 1 respond to? What 4 functions does it have?

-responds to stress

1. promotes neutrophil growth and emigration from the marrow
2. Acts with IL 6 on CNS to cause fever, depression
3. neuroendocrine effects on adrenal gland
*4. Stimulates APCs to increase Ag presentation

-antagonist is IL-1Ra

35

What does pro-inflammatory IL 1 respond to? What 4 functions does it have?

-responds to stress

1. promotes neutrophil growth and emigration from the marrow
2. Acts with IL 6 on CNS to cause fever, depression
3. neuroendocrine effects on adrenal gland
***4. Stimulates APCs to increase Ag presentation

-antagonist is IL-1Ra

36

What does IL6 a pro-inflammatory cytokine do?

-many effects redundant with Il-1
1. primary cause of fever and other constitutional signs of infection
2. T-cell "vitamin" it promotes responsiveness to IL-2, accelerates antigen activation
***3. strong growth and differentiation effects on Bcells in the presence of other B cell cytokines and effects on bone mineral metabolism where it activates osteoclasts
-it is required for optimal Th17 development
-may be required for Th-FH development

37

WHat does TNF alpha a proinflammatory cytokine do?

-Plays a central role in the immune system
1. macrophage activator
2. activator of endothelial homing and adhesion molecules
3. upregulates MHC and other cytokines
4. potent inducer of apoptosis and angiogenesis
-systemic effects that range from flu-like symptoms to death
-positive feedback

38

WHat does TNF alpha a proinflammatory cytokine do?

***Plays a central role in the immune system
1. macrophage activator
2. activator of endothelial homing and adhesion molecules
3. upregulates MHC and other cytokines
4. potent inducer of apoptosis and angiogenesis
-systemic effects that range from flu-like symptoms to death
***positive feedback

39

What does IL 8 do? When is 8 produced?

**1. NEUTROPHILS to the site of infection
-produced mainly by macs, neutrophils, and during intense inflammation by endothelial cells
-actually a chemokine

40

What does delayed hypersensitivity mean?

archaic term for TMMI

41

What is the bump from TB skin testing from?

macrophages recruited by CD4

42

What is the bump from TB skin testing from?

macrophages recruited by CD4
-less than 5% will be TB specific T cells

43

What is an example of non specific lymphocyte cytotoxicity?

Natural Killer Cells
**no Ag receptors
-older than T cells
-are not MHC restricted

44

What do Natural killer cells produce?

INF gamma

45

How do natural killer cells kill?

1. **killing mechanism suppressed by normal MHC-1
-->activated by altered MHC-1 in combination with activating ligand on the target cell

2. when pathogen complexed with antibody, natural killer cells through their Fc receptors recognize target cell with antibodies and kill it

46

What is an example of antigen specific cytotoxicity?

CD8
-recognize and kill foreign, mutated and viral infected cells
-recognition is via display of endogenously produced antigen in MHC-1 determinant

47

What do Natural killer cells produce?

INF gamma, IL21, IL2

48

When is there optimal activation of CD8?

1. NK cells
2. CD4 helper cells
4. memory cells

49

What do Natural killer cells produce?

INF gamma, IL21, IL2 (antigen activated CD4 continues to produce these)

50

What 2 things does CD8 need to be activated?

1. correct MH1 with specific antigen
2. INF gamma (produced by NK and CD4)

51

Do CD8 cells require co-stimulatory signal?

No, can kill repeatedly

52

What turns CD8 cytotxicity off?

dependent on viral display on targets, in the absence of specific targets they activate their own death by gnes Fas/FasL
-10% become memory cells

53

What turns CD8 cytotoxicity off?

dependent on viral display on targets, in the absence of specific targets they activate their own death by genes Fas/FasL
-10% become memory cells

54

What does the a dominant IL-4 cytokine cause?

Th2

55

Do Th1 and Th2 occur at the same time?

NO

56

What do B-cells recognize?

extracellular or soluble antigens

57

What are the cells that drive T0-T2?

-committed Th2 cells
-B cell presentation of antigen
-Mast Cells
-DC and TLR under specific gene influences

58

What is required for Th2 and what is that requirements major source?

Il4
major source Th2

59

What 3 cytokines are the major drivers of B cell differentiation and isotype switch?

IL 5,6, 10
-major source of these is TH2 cell

60

What 3 cytokines are the major supressors of a Th1 reaction?

Il 4, 10, 13
(13 is a critical player in IgE)

61

What 3 cytokines are the major suppressors of a Th1 reaction?

Il 4, 10, 13
(13 is a critical player in IgE)

62

What are the functions of Th2 response?

-Enhance b cell function and ultimately antibody produciton

-makes pathogens more attractive to macs and polys
-bind toxins
-target mutant/viral infected cells for killing

63

What is the costimulatory signal for the Th2 B cell response?

CD 40/ 40L

64

What is the dominant T helper response dictated by?

the type of infection, the type of TLR activated and the dominant cytokines present

65

What type of things invaders a Th 17 response?

Bacteria and Fungi that live outside of host cell

66

What do bacteria and fungi trigger?

DCs to produce TGF beta, IL6, and IL 17

67

What does Th17 produce?

IL 17

68

What does IL 17 do?

recruits neutrophils

69

Which ILs have to do with neutrophils?

8 ,7

70

Which ILs have to do with neutrophils?

8, 17

71

What does IL 17 do?

recruits neutrophils
-an inflammatory cytokine

72

Does Th17 have a central role in autoimmune disease?

yes

73

What are the cell surface markers on CD4 Th1 Regs?

3, 4, 25+ and Fox P3+

74

What are CD4 Th1 Regs influenced by and what do they depend on?

TGF beta
-depend on IL2 for survival

75

T follicular helper cells do?

-restricted to B-cell follicles in lymphoid tissue
-promotes high affinity antigen specific B cell response
-CD278, IL6, IL21

76

How does B-cell capture an antigen in the extracellular environment?

by displaying its specific angtigen receptor on its cell surface

77

What is Th17 suppressed by?

Th1 and Th2 and T regulator cells

78

When are iTregs induced?

during a normal immune response as a break mechanism on proliferation

79

What happens to stimulated T cells that do not receive co-stimulatory signals CD80 (b-7)

inactivation
convert to tregs
or commit suicide

80

That is the transcriptional factor of Tregs?

Fox P2
CD3, 4, 25+

81

That are key features of Tregs?

Fox P2
CD3, 4, 25+
and express CTLA4

82

What does CTLA4 do?

supresses T-call activation by competing with CD28 and down regulating CD80(B7) on DC

83

What is CTLA4 expression controlled by?

FoxP3

84

What is CTLA4 expression controlled by?

FoxP3
-someone gets sick and someone doesnt its cause CTLA-4 is highly polymorphic

85

Where can Tregs arise?

thymus
regional lymph nodes
peripheral sites (especially the gut)

86

What are converted to T-regs at peripheral sites during ongoing immune reactions when local cytokine concentrations begin trending to TGF-B and LESS IL6?

Tho-->Tregs

87

What happens as TGF-B becomes dominant?

-FoxP3 upregulated CTLA-4
-shuts down APC

88

Can Tregs make IL2?

NO but are dependent on it for IL2 survival and function

89

WHat strategies does the immune system ivoke to combat viral infections?

ALL STRATEGIES

90

Why is a b-cell response necessary in a viral infection?

Because the infection can leave the infected cell and that when B cells get it

91

What are CD8 memory cells called?

CD8-RM(resident memory)

92

How do CD8RM cells work?

Restrict their traffic patterns to areas of past infections and this enables them to rapidly respond to repeat infection

93

What happens to CD4-RMs when an antigen is not present?

they disappear
-when antigen is present they form clusters with macrophages

94

What do memory cells produce?

Il2, Il 21, and INF gamma that concomitantly activate an innate antiviral response

95

What is a side benefit to Memory cells/?

they prime the area of residence to be hyperreactive to viruses and presumable bacterial that were not the initial pathogens
-probably by training the macrophages by epigenetic mechanisms