Natural Killer Cells

Question 1

Natural killer cells originate from the ____ _____ and can be found in the ____, ____, and _____.

Answer 1

Natural killer cells originate from the BONE MARROW and can be found in the BLOOD, SPEEN, and LIVER.

Question 2

When do NK cells migrate to tissue in large numbers?

Answer 2

During an inflammatory reaction

Question 3

Natural Killer cells are also known as

Answer 3

Large granular lymphocytes

Question 4

Abnormal cells that NK cells kill

Answer 4

Stressed
Infected
Tumor

Question 5

Following activation in vitro with cytokines such as IL-2 and IFNy, NK cells become _____ ____ killer cells.

Answer 5

Lymphokine activated killer cells (LAK)

Question 6

All normal cells in the body express _____ on their surface.

Answer 6

MHC I molecules

Question 7

In infected cells, MHC I molecules expression is ____.

Answer 7

suppressed

Question 8

What kind of abnormal cells often fail to express MHC I molecules on their surface?

Answer 8

tumor cells

Question 9

On the surface of stressed cells, _____ and _____ are highly expressed.

Answer 9

MICA and MICB

*MHC I chain-related A and B

Question 10

Activation of NK cells is regulated by a balance between signals from _____ and _____ receptors.

Answer 10

Activating and inhibitory

Question 11

What does a high level of activating signals result in?

Answer 11

NK cell killing target

Question 12

What does a high level of inhibitory signals result in?

Answer 12

Preserves the cell. Normal MHC I expression and lack of stress markers.

Question 13

Generally, _____ signals are usually blocked by ______ signals to prevent killing of normal cells.

Answer 13

Generally, ACTIVATING signals are usually blocked by INHIBITORY signals to prevent killing of normal cells.

Question 14

In humans, cattle, cats, dogs and pigs, NK cell receptors that recognize MHC I belong to the _____ family.

Answer 14

KIR (killer cell immunoglobulin-like receptor)

*expressed on NK cells and some lymphocytes

Question 15

In mice, rats and horses, NK cell receptors that recognize MHC I belong to the ______ family.

Answer 15

KLR (killer cell lectin-like receptor)

Question 16

2 classes of KIRs

Answer 16

LILRs (leukocyte immunoglobulin-like receptors) - expressed on NK cells and some leukocytes

NKp46 - expressed only on NK cells

Question 17

What is the activating receptor for KLRs that recognizes stress proteins (MICA or MICB)?

Answer 17

NKG2D receptor

Question 18

High expression of stress proteins allows binding of ____, which overrides the inhibitory signals through MHC I and permits NK cell toxicity.

Answer 18

NKG2D

Question 19

3 important activating receptors on NK cells that bind to ligands on stressed, infected, or tumor (transformed) cells.

Answer 19

NKp46
CD16
NKG2D

Question 20

By forcing NK cells to express increased amounts of NKG2D in vitro, what effect is proposed on the body?

Answer 20

Increased expression should lead to overriding of inhibitory signals and allow NK cells to kill tumor cells.

Question 21

CD94 (NKG2A) inhibitory receptors can be blocked using an antibody to have what effect?

Answer 21

Will allow NK cells to override MHC I inhibitory signals on cancer cells and kill them

Question 22

In addition to lysing abnormal cells, NK cells also activate ______ through the release of cytokines.

Answer 22

macrophages

Question 23

3 NK cell cytotoxicity mechanisms

Answer 23

Perforin-dependent
CD95/CD95L
CD16 killing pathwy (ADCC)

Question 24

In the perforin-dependent mechanism, the NK cell releases ______ from its granules, which creates a lesion in the target cell membrane.

Answer 24

Perforin

*perforin channels

Question 25

_______ enter the target cell through perforin channels and induce apoptosis.

Answer 25

Granzymes (NK-lysin)

Question 26

In the CD95/CD95L mechanism, when ____ on the NK cell binds _____ on the target cell, apoptosis is induced.

Answer 26

In the CD95/CD95L mechanism, when CD95L on the NK cell binds CD95 on the target cell, apoptosis is induced.

Question 27

In the CD16 killing pathway (ADCC), NK cells recognize target cells through an ______ dependent pathway using the Fc receptor CD16.

Answer 27

antibody

Question 28

When an Ab binds to an Ag on an infected cell, NK cells will bind to that antibody through ____, leading to NK cytotoxicity.

Answer 28

CD16

Question 29

Cytokines that activate NK cells

Answer 29

``` IL-1 IL-2 IL-12 IL-15 IL-18 IL-21 type I and II IFNs ```

Question 30

Lymphokine activated killer cells (LAK) are NK cells that have been treated with _____ and have increased _____ capacity.

Answer 30

cytokines, cytotoxic

Question 31

Since LAK are highly toxic, they are a potential tool in the treatment of _____.

Answer 31

Cancer

Question 32

Example of a virus that inhibits NK cell cytotoxicity

Answer 32

Foot-and-mouth disease in swine

Question 33

NK cells produce ____, which enhances macrophage phagocytic activity.

Answer 33

IFN-y

Question 34

Natural Killer T cells (NKT) are from the same lineage as _____and are mostly CD4+ cells.

Answer 34

T lymphocytes

Question 35

NKT cells express ____ family receptors and mostly recognize _____ _____ on bacteria.

Answer 35

KLR | glycolipid antigens

Question 36

NKT cells are activated by ____ and link the NK cells and T cell system.

Answer 36

IL-15

Question 37

NKT cells play a role in

Answer 37

allergies anti-tumor immunity autoimmunity antimicrobial immunity

Question 38

Natural killer dentritic cells (NK DCs) spontaneously lyse ____ cells.

Answer 38

tumor

Question 39

NK DCs link the _____ and ______ immunity.

Answer 39

innate and adaptive