Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Immunology > Properties and functions of effector T cells > Flashcards

Properties and functions of effector T cells Flashcards

1
Q

What is the only cell type that can stop inflammatory actions of Th17?

A

Treg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Activation/priming of naive CD8+ T cells on encounter with antigen

A
  1. antigen specific signal
  2. co stimulatory signal
  3. cytokine signal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

The 3rd signal for Tc cell activation comes from _____ in the form of ___

A

APC; IL-12

- IL-12 directs immune responses toward CD8 Tc cell responses (adaptive cellular immune responses)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Proteins in granules of cytotoxic T cells

A

Perforin, granzymes, granulysin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Perforin

A

Aids in delivering contents of granules into the cytoplasm of target cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Granzymes

A

Serine proteases, which activate apoptosis once in the cytoplasm of the target cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Granulysin

A

Has antimicrobial actions and can induce apoptosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Cytokines

A

IFN-gamma, LT- alpha, TNF-alpha

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Cytotoxic effector molecules

A

Fas ligand

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Delivery of cytotoxins is aimed ___

A

Directly at the target cell, upon specific antigen recognition by cytotoxic T cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Cytotoxic recognition process

A

Collision and nonspecific adhesion –> specific recognition redistributes cytoskeleton and cytoplasmic components of T cell –> release of lytic granules at site of contact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Life cycle of a Tc cell

A

Antigen recognition –> activation –> clonal expansion –> differentiation into memory CD8+ T cell or effector CD8+ T cell = killing of infected target cells or macrophage activation
*differentiation occurs in the peripheral tissues, while everything else occurs in lymphoid organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Cytotoxic T cells are _____ and _____ of target cells

A

Selective; serial killers
- CTL recognizes virus-infected cell –> CTL programs target cell to die –> CTL moves to another target cell –> first target cell dies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Cytotoxic T cells kill their targets by ___

A

Inducing apoptosis

- apoptotic products will be taken up by macrophages or DC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Thymus regulatory tolerance

A

T cell specific for self antigen recognized in thymus becomes a natural regulatory T cell (aka central Tregs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Peripheral regulatory tolerance

A

T cell specific for self or commensal microbiota antigen recognized in persence of TGF-beta becomes an induced regulatory T cell (aka peripheral Tregs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Cytokines produced by Treg cells

A

IL-10 and TGF-beta

- inhibit other self-reactive T cells (located in the periphery)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What part of thymic selection eliminates autoreactive T cells?

A
  • negative selection

- T regs get rid of T cells that escape thymic elimination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

General properties of regulatory T cells

A

FOXP3+CD4+CD25+Tregs
Suppress the proliferation and IL-2 production of naive cells
- both CD4+ and CD8+ cells could be suppressed

20
Q

Effector mechanisms of regulatory T cells

A
  • Surface molecules: constitutive expression of CTLA-4 (CD152)
  • Cytokines: IL-10, TGF-beta (release of cytokines suppresses activation of all cells)
  • Cytotoxins, perforin, gransyme A, Fas-FasL
21
Q

CTLA-4

A

Molecule that inhibits activation

22
Q

Anything that ____ or _____ has a stronger binding effect

A

Regulates; inhibits

23
Q

Foxp3

A

Max transcriptional factor that directs development of T regs

24
Q

Regulatory T cells suppression mechanisms

A

Cell to cell contact dependent and soluble factor (IL-10 or TGF-beta) dependent suppression

25
Q

CTLA-4 binds to _____, sending dendritic cell into apoptosis, or an inactive state

A

CD80/86

26
Q

IL-10

A
  • potent immunomodulatory cytokine
  • anti inflammatory
  • down regulates production of Th-1 type cytokines
    • decreases expression of MHC 2 and co stimulatory molecules on DCs (tolerogenic state)
  • regulates activation/function of mast cells
  • regulates cytokine production by eosinophils
  • directly suppresses T cell proliferation
27
Q

Migration of DCs

A
  • Steady state: migrate everyday, contributes to homeostasis

- Pathogen induced: only happens during infection

28
Q

Triadic function of TGF-beta

A
  • Sword: paralyzes cell activation/differentiation to suppress immune response
  • Wand: converts naive T cells into iTregs and Th17 to aid in their combat against inflammation and infection
  • Shield: protect and maintain Tregs against apoptosis and destabilization when surrounded by inflammation and consistent stimulation
29
Q

Cytotoxins

A

Perforin, Gransyme A

30
Q

Th17 cells

A
  • physiologic role in immunity by conferring protective function against microbial pathogens
  • represent pro-inflammatory subset, which in excess contributes to autoimmunity and tissue damage
  • various subsets of Th17 cells with distinct function and pathogenic capacity
31
Q

Non pathogenic subset

A

Incapable of promoting autoimmune inflammation and might act anti-inflammatory

32
Q

Highly pathogenic Th17

A

From naive precursor cells that occur independently of TGF-beta signaling in the presence of IL-23, IL-6 and IL-1B

33
Q

Tregs vs Th17

A
  • both pathways are reciprocally interconnected, requiring a balance between both cell types = influence over outcome of immune response
  • shared requirement of TGF-B provides phenotypic and functional plasticity in both populations = differentiated cells to “re” differentiate
  • Th17 = pro-inflammatory, which can turn into autoimmune when in excess, while Tregs have antagonistic effect, that when in failure also leads to autoimmune diseases
34
Q

TH17/Treg balance provides a basis for understanding the immunological mechanisms that ______ and _______

A

Induce/regulate autoimmunity; chronic inflammation

35
Q

Therapeutic approaches

A

Targeting molecules influencing the Th17/Tregs axis

36
Q

Mechanisms that contribute to immunological self-tolerance

A
  • negative selection in the bone marrow and thymus
  • expression of tissue-specific proteins in the thymus
  • no lymphocyte access to some tissues
  • suppression of autoimmune responses by regulatory T cells
  • induction of anergy in autoreactive B and T cells
37
Q

Anergy

A

Absence of co stimulatory signal, naive T cells that have received the first signal become anergic and die by apoptosis

38
Q

Immunological tolerance

A

Non responsiveness of the lymphocyte population to the specific antigen self (self tolerance) or non-self

39
Q

Peripheral tolerance

A

Antigen recognition in the absence of the co stimulatory signal

40
Q

Co stimulatory signal and specific signal

A

Activates T cell

41
Q

Specific signal alone

A

T cell becomes anergic

42
Q

Co stimulatory signal

A

No effect on T cell

43
Q

Immunologically privileged sites

A
  • brain
  • eye
  • testis
  • uterus (fetus)
  • hamster cheek pouch
44
Q

Tolerogen

A

When an antigen induces tolerance

45
Q

The most important form of tolerance is ____

A

Non reactivity to self antigens

46
Q

Mechanisms of central tolerance

A
  • negative selection in the thymus

- autoimmune regulator (AIRE)

47
Q

Mechanisms of peripheral tolerance

A
  • absence of co stimulatory signal
  • immunologically privileged sites (immunological ignorance)
  • regulatory T cells

Immunology (28 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions