Cell-Mediated Cytotoxicity - Diebel Flashcards

1
Q

How is humoral immunity mediated and what does humoral immunity protect?

A

Mediated by Antibody

Protects extracellular environment

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2
Q

How is cell mediated immunity effective?

A

Recognizes pathogen infected cells or cells that have undergone genetic alterations and kills them

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3
Q

What does cell-mediated cytotoxicity provide defenses against?

A

Viruses
Bacteria
Parasites

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4
Q

What are antigen non-specific effector cells?

A

NK Cells (Macrophages, Neutrophils, Eosinophils)

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5
Q

What are antigen specific effector cells?

A

CD8+ T-Cells

CD4+ T-Cells

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6
Q

What does an NK cell respond to in order to mediate cytotoxicity?

A

Lack of MHC Class I Molecule

Stress Induced Activating Ligand

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7
Q

What does a CD8+ T-Cell respond to in order to mediate cytotoxicity?

A

Antigen recognition as Non-Self

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8
Q

CTL-Precursors lack the ability to do what?

A

Proliferate and Kill

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9
Q

How is a CTL-P activated?

A

Licensed APCs

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10
Q

How are APCs licensed?

A

Th1 or Th17 CD4+ T-Cells

PAMPs on TLRs

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11
Q

What signals from the APC is required to activate a CTL-P?

A

Antigen presented on MHC Class I
CD28 :: CD80/86
IL-2 from Th1 or Th17
IL-4, IL-13, IL-15

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12
Q

Describe the alpha receptor on a naive CD8+ T-Cell

A

Low affinity IL-2 Receptor

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13
Q

Describe the CD25 receptor

A

High affinity Gamma, Beta and Alpha IL-2 Receptor

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14
Q

What do naive CTL-P cells express?

A

Low levels of CD44 and LFA-1
High levels of L-Selectin and CCR7 (retention in lymph node)
NO IL-2

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15
Q

What do effector CTL cells express?

A

High Affinity IL-2R (CD25) and IL-2
Low levels of L-Selectin and CCR7
High levels of CD44 and LFA-1

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16
Q

What do memory CTL cells express?

A

Low levels of IL-2

17
Q

CTL LFA-1 binds tightly to…

A

ICAM on target cell

18
Q

Environmental IL-4, IL-12, and IL-15 induces the CTL to produce what?

A

Perforin and Granzymes

19
Q

How do granzyme molecules activate apoptosis?

A

Cleavage of caspases (Bid and Procaspase-3)

20
Q

What are the 3 mechanisms that CTLs and NK Cells can kill by?

A

1) Perforin and Granzyme Secretion
2) Fas-Fas Ligand binding
3) TNF production and secretion

21
Q

CTL CD2 binds to…

A

LFA-3

22
Q

What type of cells kill virus infected cells, intracellular pathogen-infected cells, and tumor cells?

A

NK Cells

23
Q

What cytokines stimulate NK cell activity?

A
IFN-a
IFN-B
IFN-y
TNF-a
IL-15
24
Q

Differentiate between CD56 high and low cells.

A

NK Cells with CD56 high are target cell killers.

NK Cells with CD56 low are cytokine (IFN=y) releasing.

25
Q

What do NK cells express on their surface?

A

CD16 (FcyRIIIA) and NKRs

26
Q

What do Lectin-Like Receptors (NKG2 family) do on NK Cells?

A

Binds HLA-E and MHC Class I-like molecules (NKG2D)
-Associated with CD94
ACTIVATING

27
Q

What do immunoglobulin-like receptors (KIR) do on NK Cells?

A

Killer Cell Immunoglobulin-Like Receptors bind MHC Class I Molecules
INHIBITORY

28
Q

NK Cells recognize what when looking to kill target cells?

A

Cells that MASK the presence of foreign antigen on MHC Class 1

29
Q

CTLs recognize what when looking to kill target cells?

A

Cells that EXPRESS foreign antigen on MHC Class I

30
Q

What effector cells are associated with Antibody-Dependent Cell Mediated Cytotoxicity (ADDC)?

A
NK Cells
Macrophages
Monocytes
Neutrophils
Eosinophils
31
Q

What effector cells release cytolytic enzymes for cell killing?

A

Macrophages
Eosinophils
Neutrophils

32
Q

What effector cells release TNF for cell killing?

A

NK Cells
Monocytes
Macrophages

33
Q

What effector cells release Perforin for cell killing?

A

NK Cells

Eosinophils

34
Q

What effector cells release Granzyme for cell killing?

A

NK Cells

35
Q

What are the 4 Antibody Effector Functions?

A

1) Virus and Toxin Neutralization to prevent pathogen-host binding
2) Opsonization to facilitate phagocytosis
3) Complement fixation and formation of the membrane attack complex to facilitate phagocytosis or lysis
4) Antibody-Dependent Cell Mediated Cytotoxicity (ADCC) to facilitate NK-induced apoptosis

36
Q

What are the 5 functions of Fc Receptors?

A

1) Degranulation
2) Opsonization of Bacteria and Phagocytosis
3) Maintaining serum antibodies
4) ADCC
5) Transcytosis into secretions