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MI and Genomics > MI 03b: T Cell Activation > Flashcards

MI 03b: T Cell Activation Flashcards

1
Q

Goals of T cell activation: to generate (X) and (Y).

A 
X = large number of effector cells
Y = antigen-specific memory T cells
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2
Q

What defines a “naive” T cell?

A

Hasn’t encountered antigen yet (recirculating)

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3
Q

Epithelial barrier is breached. Microbes and their products are taken up by (X), which process the protein components into (Y) for MHC presentation.

A 
X = dendritic cells
Y = peptides
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4
Q

As DCs process antigen, they migrate from (X) to (Y).

A 
X = infected tissue
Y = T cell zones (draining lymph nodes)
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5
Q

T/F: During migration to T cell zone, DCs upregulate expression of MHC and co-stimulatory molecules.

A

True

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6
Q

T/F: Upon activation, T cell leaves the lymph node right away.

A

False - stays in lymph node for few days

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7
Q

T cell activated. Which subsequent processes occur prior to it leaving lymph node?

A
  1. Receptors and signaling pathways activated
  2. Surface molecules change
  3. Cytokines produced
  4. Clonal expansion
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8
Q

The cytokine (X) is particularly important in T cell proliferation.

A

X = IL-2

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9
Q

T cell activation: Signals from different (X) enable differentiation of CD4 T cells to (Y) or CD8 T cellsto (Z).

A 
X = cytokines;
Y = helper T cells
Y = cytotoxic T cells
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10
Q

In normal, healthy T cell response, expansion and decline of responses occurs over (X) period of time.

A

X = 1-2 weeks

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11
Q

Blood-borne pathogens are captured by (X) cells, primarily in (Y) location.

A 
X = APCs 
Y = spleen
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12
Q

T/F: DCs are the best APCs.

A

True

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13
Q

What are the classes of DCs?

A
  1. Classical

2. Plasmacytoid

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14
Q

(X) class of DCs is the primary source of (Y), which are crucial for anti-viral immune response.

A 
X = plasmacytoid
Y = Type I IFN
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15
Q

Which class of DCs primarily responsible for presenting antigen to naive T cells?

A

Classical

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16
Q

Unstimulated DCs typically reside in:

A

Epithelial and sub-epithelial tissue layers

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17
Q

What do bored, unstimulated DCs typically do in their spare time?

A

Very mobile and phagocytic (constantly sample environment for microbes)

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18
Q

T/F: DCs themselves may be infected by viruses.

A

True

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19
Q

It’s typically (X) binding to (Y) of DCs that begin their maturation process.

A 
X = PAMPs
Y = PRRs (i.e. TLRs)
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20
Q

As DCs take the trip to T cell zones, which of their molecules are (up/down)-regulated?

A

Up-regulate:

  1. MHC
  2. B7 co-stim
  3. ICAM-1 (integrin ligand)
  4. CCR7 (chemokine receptor)
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21
Q

Which integrin (receptor/ligand) is up-regulated on migrating DCs?

A

Ligand;

ICAM-1

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22
Q

Maturing DCs know the path to T cell zone because they (gain/lose) (X) and (gain/lose) (Y).

A

Lose;
X = adhesiveness to epithelial cells
Gain;
Y = expression of CCR7 chemokine receptor

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23
Q

Migrating DCs express (X) receptor, which directs them toward (Y) via chemotaxis. The chemokines are produced by (Z).

A 
X = CCR7
Y = Z = lymph nodes
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24
Q

(One/hundreds) of naive T cells will interact with (one/hundreds) of DCs in any given day.

A

One; hundreds

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25
Q

Which signals are necessary for T cell activation?

A
  1. Antigen recognition

2. Co-stimulation

26
Q

T/F: TCR is a signaling molecule.

A

False

27
Q

T/F: TCR is non-covalently associated with signaling molecules.

A

True

28
Q

TCR of naive T cell binds complementary peptide-MHC complex. Signal transduction occurs via which molecule(s)?

A

CD3 and zeta chains

29
Q

T/F: Signal 2 of T cell activation involves CD4/CD8 co-receptors.

A

False - they’re involved in signal 1

30
Q

(X) co-receptors on T cells increase binding (affinity/avidity) between TCR and APC. This is involved in Signal (1/2) of T activation.

A

X = CD4 or CD8
Avidity;
Signal 1

31
Q

Signal 2 of T activation provided by binding of (X) to (Y).

A 
X = CD28 on T cell
Y = B7 on DC
32
Q

There’s (positive/negative) feedback in Signal (1/2) of T activation. Describe this.

A

Positive;
Signal 2;

T cells further up-regulate CD28 expression upon receiving co-stimulatory signal from DCs

33
Q

In general, T activation signals 1 and 2 work together. Signal 1 provides (X). Signal 2 provides (Y).

A 
X = specificity
Y = protection against autoimmunity
34
Q

T cell activation: T cell contains integrin (receptor/ligand) (X) that binds to (Y) on APC.

A

Integrin receptor
X = LFA-1;
Y = integrin ligand (ICAM-1)

35
Q

It’s important to avoid (over/under)-production of (X) cytokine, a potent T-cell growth factor. How is this done?

A

Over-production;
X = IL-2;
Its mRNA is inherently unstable

36
Q

Signaling from T cell activation causes which events to occur, in terms of IL-2 production?

A

Increased IL-2 production via:

  1. Stabilization of mRNA
  2. Up-regulate transcription factors
37
Q

Activated T cells have (more/less) (receptors/affinity) for IL-2.

A

More receptors and increased affinity

38
Q

IL-2 in T cell activation has (autocrine/endocrine/paracrine) actions.

A

Autocrine (same cell) and paracrine (nearby T cell)

39
Q

Which region(s) of which cell(s) constitute the immunological synapse?

A

Contact region between T cell and APC

40
Q

Within immunological synapse (on T cell), (X) receptors/molecules cluster and (Y) are pushed to periphery.

A 
X = TCR, co-receptors, and CD28
Y = LFA-1
41
Q

Lck is a(n) (X) that’s associated with (Y) in/on (surface/cytosol) of (Z) cell.

A

X = tyrosine kinase;
Y = CD4 or CD8 co-receptors
Cytosol;
Z = T cell

42
Q

Lck action.

A

Phosophorylation of ITAMs on CD3 and zeta chains

43
Q

ITAMs are (X)-based activation motifs found on (Y) in (Z) cell.

A 
X = Tyrosine;
Y = CD3 and zeta chains
Z = T cell
44
Q

(Dephosphorylated/phosphorylated) ITAMs stimulate signaling along which pathways?

A

Phosphorylated;

  1. PLC(gamma)
  2. Ras/Rac
  3. PI3 kinase
45
Q

T cell signaling pathways final generated products.

A

Transcription factors (NFAT, NFkB, AP-1)

46
Q

T cell signaling pathways are important targets for (X) drugs.

A

X = immunosuppressive

47
Q

(X) cells are unique in having the capacity to bypass rules of antigen presentation via cross-presentation. Explain.

A

X = dendritic

Microbe phagocytosed (MHC II loading) and, during processing, some antigen spills into cytosol (now also available for MHC I loading)

48
Q

There’s a safeguard in place for differentiation of CD(4/8) T cells into cytotoxic T cells. What’s the safeguard?

A

CD8;

CD4 T cells must be co-activated (produce cytokines that aid differentiation)

49
Q

Some pathogens secrete (X), which induce unspecific activation of many CD(4/8) T cells and massive release of (Y).

A

X = super-antigens;
CD4;
Y = cytokines

50
Q

List the subsets of T helper cells that CD(4/8) T cells can differentiate into.

A

CD4;

Th1, Th2, Th17, Tfh

51
Q

Difference between Th1, Th2, and Th17 cells is essentially which (X) they (Y).

A 
X = type of pathogen
Y = are programmed to fight
52
Q

Tfh, aka (X), cell has key role of:

A

X = follicular helper T cell

assisting B cells with Ab production

53
Q

T/F: The T helper (effector) cells don’t exit peripheral lymphoid organs.

A

False - only Tfh doesn’t exit

54
Q

List the general types of receptors expressed on T cells that allow for their migration/trafficking.

A
  1. Chemoattractant receptors
  2. Selectins
  3. Integrins
55
Q

Naive T cells express which receptor(s) to direct their trafficking to (X)?

A
  1. CCR7
  2. L-selectin
  3. LFA-1 (integrin)

X = T cell zone

56
Q

Naive T cells migrate from (X) into (Y) through (Z) structures.

A 
X = blood circulation
Y = lymph node T cell zone
Z = high endothelial venules (HEVs)
57
Q

(X) are specialized endothelial cells that facilitate (slowing/speeding) of T cells through which interactions?

A

X = HEVs;
Slowing;

  1. L-selectins
  2. Integrins (ICAM-1 and LFA-1)
58
Q

L-selectin (ligand/receptor) on naive T cell interacts with (X) (ligand/receptor) on (Y) during migration.

A

Receptor;
X = L-selectin
Ligand;
Y = HEVs

59
Q

Integrin (ligand/receptor) (X) on naive T cell interacts with integrin (ligand/receptor) (Y) on (Z) during migration.

A 
Receptor;
X = LFA-1;
Ligand;
Y = ICAM-1;
HEV
60
Q

Activated effector T cells, unlike naive T cells, are not drawn into (X) due to lack of expression of (Y) (receptor/ligand).

A

X = peripheral lymph organs;
Receptors
Y = CCR7 and L-selectin

61
Q

To exit lymph nodes, (activated/unactivated) T cells up-regulate expression of (X). This will help them leave because (Y) is (higher/lower/absent) in blood.

A

Unactivated (circulating);
X = Sphingosine-1-P (S1P) receptor;
Y = S1P;
Higher

62
Q

If T cell activated in lymph node, its exit is (facilitated/supressed) by (activation/suppression) of (X).

A

Supressed;
Supression
X = S1P receptor levels

MI and Genomics (16 decks)

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