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Immunology > chapter 10 > Flashcards

chapter 10 Flashcards

1
Q

T cells require _______________as a first signal.

A

antigen presentation

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2
Q

Once activated, T cells differentiate into their ____________________forms.

A

effector

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3
Q

Successful T cell–APC interactions organize signaling molecules into an ____________________, which consists of TCR/MHC-peptide complexes and adhesion molecules/bound ligands.

A

immunological synapse

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4
Q

additional signal that is required to induce proliferation of antigen-primed T cells and is generated by interaction of CD28 on T cells with CD80/86 on antigen-presenting cells

A

costimulatory signal

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5
Q

What is required for optimal T-cell activation and proliferation?

A

costimulatory signals

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6
Q

costimulatory signal 1:

A

antigen-specific TCR engagement

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7
Q

costimulatory signal 2:

A

contact with costimulatory ligands

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8
Q

costimulatory signal 3:

A

cytokines directing T-cell differentiation into distinct effector cell types

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9
Q

function of positive costimulatory receptors?

A

facilitate activation
-examples are CD28 ICOS

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10
Q

function of negative costimulatory receptors?

A

help turn activation off
-examples are CTLA-4, PD-1, and BTLA

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11
Q

describe CD28 and its functions:

A

-Generally involved in initial activation events in T cells
* 44 kDa glycoprotein homodimer expressed on majority of T cells
* Markedly enhances TCR-induced proliferation and survival
* Binds to B7-1 and B7-2 expressed by APCs

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12
Q

describe ICOS and its functions:

A

-expressed on memory and effector T cells
-inducible costimulator, binds ICOS-ligand on activated APCs
-may help to maintain activity of already differentiated cells

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13
Q

describe CTLA-4 and its functions:

A

-Induced within 24 hours after activation, peaks 2–3 days post-stimulation
- Binds to B7-1/B7-2 with higher affinity than CD28 but shuts down signaling pathways (“putting the brakes on”)

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14
Q

What does PD-1 stand for?

A

program death 1

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15
Q

what does BTLA stand for?

A

B- and T-lymphocyte attenuator

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16
Q

may help to mediate T-cell tolerance in nonlymphoid tissues

A

PD-1

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17
Q

may downregulate inflammatory and autoimmune responses

A

BTLA

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18
Q

-a physiological state in which cells are unable to be activated by antigen
-results if a costimulatory signal is absent
-helps provide tolerance
-if only signal 1 is received, the cell is rendered nonresponsive

A

clonal anergy

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19
Q

Which signal do cytokines provide?

A

signal 3

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20
Q

describe how IL-2 is an example of an autocrine type of cytokine response system:

A

-T cells produce the cytokine and receptor for it
-binding of this ligand induces a very strong proliferation signal during activation stages

21
Q

what type of characteristic costimulatory properties do APC cells have?

A

they provide the right signals to activate T cells

22
Q

Viral/bacterial proteins that bind to specific Vβ regions of TCRs and α chain of class II MHC molecules

A

superantigen

23
Q

superantigens non-specifically, effectively “short-circuits” TCR and MHC-peptide, which produces what?

A

dramatic cytokine secretion by large proportion
of inappropriately activated T cells

24
Q

Initial activation signals 1 and 2 induce:

A

-upregulation of prosurvival genes
-transcription of IL-2 and IL-2R genes
-outcome is activation and proliferation

25
Q

Differentiation of T helper cell subsets is regulated
by_______________________

A

polarizing cytokines

26
Q

Factors that are added to a vaccine mixture to enhance
the immune response to antigen by activating innate immune cells

A

adjuvants

27
Q

What are the functions of TH1?

A

-enhances APC activity
-enhances Tc activation
-protects against intracellular pathogens
-involved in delayed type hypersensitivity, autoimmunity

28
Q

What are the functions of TH2?

A

-protects against extracellular pathogens
-involved in allergy

29
Q

What are the functions of TH9?

A

-protects against extracellular pathogens
-involved in mucosal autoimmunity

30
Q

What are the functions of TH17?

A

-protects against fungal and extracellular bacterial infections
-contributes to inflammation, autoimmunity

31
Q

What are the functions of TH22?

A

-protects against extracellular pathogens
-involved in inflammatory skin disease

32
Q

What are the functions of Treg?

A

-inhibits inflammation
-inhibits antitumor responses

33
Q

What are the functions of TFH?

A

B cell help in follicles and germinal centers

34
Q

TH1 regulate immunity to ________________________.

A

intracellular bacteria and viruses

35
Q

TH2 regulate immunity to _____________.

A

worms

36
Q

TH17 regulate immunity to_______________________.

A

extracellular bacteria and fungi

37
Q

TREG are inhibitory in terminating ___________________ and inhibiting
_________________________

A

immune responses
autoimmunity

38
Q

What type of immunity is regulated by TFH?

A

humoral

39
Q

-Polarizing cytokines: IL-12, IL-18, and IFN-γ induce TH1
differentiation
-Master gene regulator: T-bet
-Effector cytokines: strong IFN-γ production
» Leads to class switching to IgG classes
» Supports differentiation of antiviral CD8+ killer T cells

A

Differentiation and function of TH1 cells

40
Q

-Polarizing cytokines: IL-4 induce TH2 differentiation
-Master gene regulator: GATA3
-Effector cytokines: IL-4, IL-5, and IL-13 production
» IL-4 acts to promote activities of eosinophils against worms
» IL-4 induces class switching to IgE

A

Differentiation and function of TH2 cells

41
Q

describe how cytokines achieve cross regulation:

A

– IFN-γ (Th1) inhibits IgG1/IgE class switching (Th2)
– IL-4 (Th2) inhibits production of IgG2a (Th1)
– IL-10 (Th2) inhibits TH1 responses from APCs

42
Q

describe how master regulators commit T cells to one subset and against
the other:

A

– T-Bet (Th1) suppresses TH2 pathway gene expression
– GATA3 (Th2) suppresses TH1 pathway gene expression

43
Q

-Polarizing cytokines: IL-6 and TGF-β
-IL-23 also plays a role in finalizing the subset commitment
* Master gene regulator: RORγt
* Effector cytokines: IL-17A, IL-17F, and IL-22
– IL-17A produced is associated with chronic inflammatory and
autoimmune responses
– IL-17F and IL-22 produced may play a role in warding off fungal and
extracellular bacterial infections

A

Differentiation and function of TH17 cells

44
Q

-Polarizing cytokines: TGF-β
* Master gene regulator: FoxP3
* iTREG cells secrete IL-10 and TGF-β to downregulate inflammation
(by inhibiting APCs) and suppress other T- cell subsets

A

Differentiation and function of (induced) TREG cells

45
Q

increases in response to activation signals

A

CD44

46
Q

an adhesion protein

A

CD62L

47
Q

a chemokine receptor

A

CCR7

48
Q

Which of the following conditions would lead to T-cell anergy?
a. A naïve T-cell interaction with a dendritic cell in the presence of CTLA-4 Ig
b. A naïve T cell stimulated with antibodies that bind both the TCR and CD28
c. A naïve T cell stimulated with antibodies that bind only the TCR
d. A naïve T cell stimulated with antibodies that bind only CD28

A

a & c

Immunology (18 decks)

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