Natural Killer Cells

Question 1

Size, disitribution, function.

Answer 1

Large cells. Make of 5-10% of lymphocytes, can lyse cells

Question 2

Marker for human NK cells

Answer 2

CD16

Question 3

NK cells doesn’t have…

Answer 3

TCR

Question 4

Two NK cell functions

Answer 4

Indirect: secretion of IFNγ, Direct: secretion of cytolytic granules.

Question 5

Primary cytokine capable of activating NK cells

Answer 5

IL-12

Question 6

Stages in cytotoxic killing:

Answer 6

1: formation of immune synapse, 2: cytoskeletal rearrangement, 3: lytic granules deployed, 3: target cell killed

Question 7

Mode of killing by NK cells

Answer 7

Apoptosis

Question 8

Perforin

Answer 8

Makes holes in cell membrane

Question 9

Granzymes

Answer 9

Activates caspases

Question 10

Triggers of NK cell killing:

Answer 10

Antibody mediated, recognition of stressed ligands, recognition of lack of MHC class I.

Question 11

Antibody-mediated

Answer 11

Recognition of antibody by CD16 (FcγIIIA)

Question 12

NK inhibitory receptors

Answer 12

Bind to MHC I

Question 13

Stress induced ligands

Answer 13

MHC-like molecules, binding activating receptors on NK cells

Question 14

NKG2A

Answer 14

Lectin-like. Inhibitory. Binds eg. MHCI, HLA-E

Question 15

NKG2D

Answer 15

Lectin-like. Binds eg. MHC I - like molecules. Stress proteins. MIC-A, B

Question 16

Variegated expression

Answer 16

Any one NK cells expresses a different subset of receptors.

Question 17

HLA-E

Answer 17

Present peptide cleaved from other MHC molecules. Is a marker for amount of MHCI expressed at any point.

Question 18

Inhibitory signal

Answer 18

Receptor binding causes ITIM phosphorylation. Recruits SHP-1. SHP-1 dephosphorylates VAV1.

Question 19

VAV1

Answer 19

Key intermediate in NK cell activation.

Question 20

Activating signal

Answer 20

ITAM phosphorylation recruits DAP10. DAP10 feeds into activation of PI3K. Activation of VAV1

Question 21

KIRs

Answer 21

Bind to allele specific HLA-A, B, C. Kan be activating or inhibitory.

Question 22

Allele specificity

Answer 22

Lower for A, B and C HLA. Most receptors are specific for C. But some are for A and B as well

Question 23

NK cell education

Answer 23

Immature NK cells bind with inhibitory KIR to self-HLA-C. Activating receptors activate them self as to cancel out inhibitory signal. Any signal disturbing this balance will be regarded as aberrant.

Question 24

Need for NK cells

Answer 24

Good for virus resistance

Question 25

MCMV-cells

Answer 25

Express m157, which binds activating receptor Ly49H. Mice without are more susceptible.

Question 26

Memory?

Answer 26

Some indication of a kind of memory.