Exam 2: How T Cells Work (Ch.6) Flashcards Preview

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Flashcards in Exam 2: How T Cells Work (Ch.6) Deck (40)
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1
Q

What are the two jobs of Helper T Cells?

A
  1. remain in blood and lymph nodes providing help for B cells and CTLs
  2. Leave the blood and enter battle sites providing help for soldiers on the front line
2
Q

What are communication proteins for the immune system and others and are used to drive the immune system in a particular direction?

A

cytokines

3
Q

How do Helper T cells send the signal “for help” out?

A

cytokines

4
Q

What type of cells provide “education” regarding type of invader and location of invader?

A

dendritic cells

5
Q

What are the “two signals” that provide information to dendritic cells so they know what’s going on?

A
  1. PRR’s (pattern recognition receptors), such as TLRs on dendritic cells recognize PAMPs (pathogen ass. molecular patterns) on invaders
  2. Cytokines produced by cells in the area under attack
6
Q

What are two examples of PRRs on dendritic cells that recognize PAMPs on invaders?

A
  • TLR4 recognizes LPS

- TLR3 recognizes dsRNA

7
Q

What information do cytokines produced by cells in the area under attack provide the dendritic cell with? (3)

A
  1. indicate particular location in body (where)
  2. diff pathogens elicit diff cytokines (type/what))
  3. cells from diff areas of body make diff combinations of cytokines
8
Q

What should we think of cytokines as?

A

address for anatomical location (where) and pathogen identity (what)

9
Q

T/F. Cytokines released by dendritic cells convince T cells to express specific sets (profiles) of cytokines.

A

True — we give these T cells diff names based on their cytokine profile (Th1, Th2, Th9, Th17, Th22, Treg, Tfh)

10
Q

What type of T helper cell is used for Viral or Bacterial Attack?

A

Th1 Helper T Cells

11
Q

What do Th1 Helper T cells react to, and why type of cytokines do they release?

A

viral and bacteria attacks

Classical Cytokines

  • TNF
  • IFN-gamma
  • IL-2
12
Q

What is the goal of Th1 Helper T cells?

A
  • activate macrophages and natural killer cells
13
Q

What will IFN-gamma, release by Th1 Helper T cells do?

A

(viral or bacteria attack)

  • keeps macrophages active
  • tells B cells to make IgG3 (opsonizes viruses and bacteria and fixes complement)
14
Q

What does IL-2, released by Th1 Helper T cells do?

A

(viral and bacteria attack)

  • recharges NK cells
  • stimulates proliferation of CTLs, NK cells, and more TH1 cells
15
Q

What type of Helper T cells is used for a parasitic attck or food contaminated with pathogenic bacteria?

A

Th2 Helper T cells

16
Q

What do Th2 Helper T cells respond to? What type of cytokines do they release?

A

parasitic attack or food contaminated with pathogenic bacteria–> intestines under attack

  • IL-4
  • IL-5
  • IL-13
17
Q

What is the goal of the three cytokines released by Th2 Helper T cells in response to a parasitic attack?

A

IL-4 –> growth factor to proliferate T cells and for B cells making IgE

IL-5 –> causes B cells to make IgA (antibacterial in the GI)

IL-13 –> stimulates mucus in intestine

18
Q

What type of T Helper cell is used from fungal attack and muscosal barriers?

A

Th17 Helper T cells

19
Q

What do Th17 T Helper cells respond to? an what cytokines do they release?

A

fungal attack and mucosal barriers

IL-17
IL-21

20
Q

What do the two cytokines released by Th 17 T Helper cells in response to a fungal and muscoal barriers attack do?

A

IL-17 –> recruits massive numbers of neutrophils to the area

IL-21 –> causes growth of more Th17 cells

influence production of opsonizing antibody

21
Q

What do Dendritic cells make that cause help T cells to make Th17 cytokines?

A

dendritic cells make TGF-beta and IL-6

22
Q

What do Th1 Helper T cells recruit?

A

(ass. with viral and bacteria attack)
- macrophages
- CTLs
- NK cells

23
Q

What do Th2 Helper T cells recruit?

A

(ass. with parasitic attack and intestines under attack)
- B cells
- IgA and IgE production

24
Q

What do Th17 Helper T cells recruit?

A

(ass. with fungal attack and mucosal barriers)
- neutrophils
- opsonizing Ab production

25
Q

What type of Helper T cells are waiting until they enter the tissue to determine Th type based on cytokines present and are non committed T cells and will change based on cytokine env.?

A

Th0 Helper T cells

26
Q

T/F. Cytokines have a very wide range on where can have impact.

A

False– they have a very limited range (local impact only)

27
Q

Once a helper T cell starts making a certain type of cytokine profile, what is it considered?

A

it is committed

28
Q

What do cytokines released by helper T cells promote and inhibit?

A

Promote–> their Th subset

Inhibit –> other Th subsets

Ex: Th2 cells make IL-10 which inhibits production of Th1 subset

29
Q

What are Superantigens?

A
are a special class of T-cell activators:
= viral/bacterial proteins that bind to specific regions of TCRs and class MHC II molecules 

produce dramatic cytokine secretion by large proportion of inappropriately activated T cells

30
Q

What are a special class of T-cell activators that are viral or bacterial proteins that bind to specific regions of TCRs and class II MHC molecules and produce dramatic cytokine secretion by large proportion of inappropriately activated T cells?

A

Superantigens

(over activation of T helper cells)

Ex: TSST– toxic shock syndrome toxin

31
Q

What does a Naive CTL (killer t cell) need for activation?

A

a licensed dendritic cell presenting cognate Ag on a MHC I and co-receptors and co-stimulation occur

32
Q

How do we license a dendritic cell, which has the ability to activate a naive CTL?

A
  • T-helper cell help
  • dendritic cell directly recognizes PAMPs
  • “license” the dendritic cell to present exogenous protein to MHC1
33
Q

How do Helper T cells control the size of the response?

A

by dictating (through cytokines) the number of killer T cells being activated

34
Q

What are the two ways the Killer T cells kill?

A
  1. CTL delivers a package with perforin and granzyme B

2. CTL connects its Fas ligand to the Fas protein on the target cell

35
Q

What occurs when a Killer T cell (CTL) delivers a package with perforin and granzyme B?

A
  • perforin pokes holes in a membrane

- granzyme B initiates a chain rxn –> leading target cell suicide = apoptosis

36
Q

What occurs when a Killer T cell (CTL) connects its Fas ligand to the Fas protein on the target cell?

A

Fas protein signaling causes cells to commit suicide

37
Q

What type of death means enzymes and chemicals from the dying cell are released into surrounding tissue and is extremely damaging?

A

necrosis

38
Q

What type of death means the enzymes and chemicals from the dying cell are neatly contained in vesicles and the vesicles are eaten and disposed of by macrophages?

A

apoptosis

39
Q

What is the co-receptor for a helper T cell?

What about for a killer T cell?

A

Helper–> CD4 –> emits cytokines

Killer–> CD8 –> kills target cells

40
Q

Describe the difference b/w nairve t cells and experienced t cells.

A

Naive T cell–> to be activated need two signals:

  • w/o both signals get anergy
  • with both signals get activation

Experienced/activated T cells–> travel to site of inf. and help/kill and may NOT need secondary signal to do so