T cell Function & Destruction of Cell-Associated Invaders (16) Flashcards

1
Q

What are the accessory molecules for cytotoxic T cells?

A

CD8

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2
Q

Cytotoxic T cells recognize antigen on MHC [I/II]

A

MHC I

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3
Q

Once they encounter an antigen, they clonal expand, differentiate, and develop a killing machinery in the ________

A

cytoplasm

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4
Q

Cytotoxic T cells are important in protection from [extracellular/intracellular] microbes that cause the synthesis of foreign proteins in the cytoplasm such as viruses

A

intracellular

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5
Q

What is the result of cytotoxic T cells doing its job?

A

apoptosis of the target cell

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6
Q

What is apoptosis?

A

programmed cell death or cell suicide
involves the controlled dismantling of intracellular components while avoiding inflammation and damage to surrounding cells

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7
Q

T/F: Apoptosis causes inflammation and damage secondarily to surrounding cells

A

FALSE - this is necrosis

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8
Q

What are the morphological hallmarks of apoptosis?

A

DNA fragmentation
membrane blebbing

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9
Q

What are the two major pathways of apoptosis?

A

intrinsic or mitochondrial pathway
extrinsic or death receptor pathway

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10
Q

What are caspases?

A

endopeptidases that are important in maintaining homeostasis through regulating apoptosis and inflammation

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11
Q

What are initiator caspases?

A

activated by multi molecular death complexes
2, 8, 9, 10, 14 (dont worry about number)

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12
Q

What are effector caspases?

A

break down cellular structures
3, 6, 7

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13
Q

What are inflammatory caspases?

A

activated by multi molecular inflammasomes
1, 4, 5, 11

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14
Q

What are some triggers of the intrinsic pathway of apoptosis? Which caspase is activated?

A

cell stress
DNA damage
caspase 9

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15
Q

Cytotoxic T lymphocytes have a ligand called ______. When combined with a death receptor called ______, disc, or death-inducing signaling complex begins

A

CD95L
CD95

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16
Q

Apoptotic bodies are taken up by ______

A

macrophages - inhibits inflammation

17
Q

What are the main steps in cytotoxic T cell responses?

A

antigen recognition and binding of CTL to target cell
CTL activation and granule exocytosis
apoptosis of target cell

18
Q

What are the proteins released with CTL activation and granule exocytosis

A

granzymes
perforin

19
Q

What are the 5 stages of cytotoxic T cell response?

A
  1. activation of naive CTL by a DC in a secondary lymphoid tissue
  2. CTL —> daughter cells (pre-CTLs)
  3. differentiation of pre-CTL in an inflammatory site into an “armed” CTL
  4. activation of armed CTL by non-self peptide on MHC Class I
  5. CTL-mediated destruction
20
Q

What are the 3 signals for cytotoxic T lymphocytes to be activated/armed?

A
  1. IL-12 by dendritic cells
  2. interaction with cytotoxic T lymphocytes with antigen on MHC I
  3. IF-gamma, IL-2 (produced by T-helper cells)
21
Q

What are the zones in the cytotoxic T cell?

A

central zone —> CD95-ligand perforins
central zones —> TCR/CD3, CD28/CD80

22
Q

What is the perforin pathway of cell killing?

A

punch hole into cell
CTL reorganizes and brings cytotoxic granules to the site of CTL-target cell contact

23
Q

What is perforin?

A

a pore-forming protein

24
Q

What are granzymes?

A

a family of serine proteases

25
Q

What is the CD95 or Fas pathway of T cell mediated cytotoxicity?

A

regulates T-cell survival
get rid of unwanted T cells

26
Q

Naive cytotoxic T cells [do / do not] express Fas-ligand (FasL or CD95L) but after activation and conjugate formation, _____ is expressed on the CTL surface

A

do not
FasL

27
Q

Engagement of Fas on a target cell by FasL or CD95L expressed by an armed CTL results in _______

A

the death of the target cell by apoptosis

28
Q

What produces perforins or granzymes?

A

cytotoxic T-lymphocytes

29
Q

What is the most efficient pathway for killing target cell?

A

cytotoxic T-cell releasing perforins and granzymes
MHC restricted - ONLY one that is, antigen is presented on MHC
- macrophages, neutrophils, and NK cells not MHC restricted

30
Q

Which types of cells are not MHC restricted when killing target cells?

A

macrophages
neutrophils
natural killer cells

31
Q

Activated macrophages are capable of killing _______

A

resistant intracellular bacteria

32
Q

How are macrophages activated to kill mycobacteria?

A

Th1 cell is important in aiding macrophages! IF-gamma and IL-2
NK cells can also do this but is incomplete

33
Q

[M1/M2] macrophages are important in repair such as wound healing and immune regulation, and [M1/M2] is important in increased antimicrobial activities like with intracellular bactera

A

M2: repair
M1: antimicrobial