Nk cells II

Question 1

What is licensing?

Answer 1

Tunes NK cells to their microenvironment, makes sure that if they see lots of inhibitory signal, that they can become more responsive to decreases.
If they see lots of activator signals at stable state, then you need them to be less responsive and require higher levels of activatory signals to respond.

Question 2

If in NK development, NK cells are exposed to stronger inhibitory R:L interactions, will NKs be hyper or hypo responsive?

Answer 2

They will be hyper reponsive.

Question 3

If NK cells are develped in MHC 1 deficient mice, will they be hyper or hyporesponsive?

Answer 3

They will reeive weaker inhibtiory signals in licencing and will be hyporesponsive.

Question 4

If NK cells licensed (but have no inhitiroy receptors for MHC 1) will they be hyper hypo responsive?

Answer 4

They receive almost no inhbitory signals, so hyporesponsive.

Question 5

If NK cells that express activatory receptors NKG2D and murine Ly49H in trangenic mice expressing their lgiands, hypo or hyper responsive?

Answer 5

They receive more activatory signals during licensing, so will be hyporesponsive (think that in environemtn there is higher levels of activator signals it has to ‘ignore’).

Question 6

If you lack activing receptors, will NK cells be hyper or hypo responsive during licensing?

Answer 6

They will not receive any activatory signals, assume environment has no activator signals, to compensate need to be hyperreactive.

Question 7

What models for licencisnig are there?

Answer 7

arming, disarming, rheostat.

Disarming theory f

Question 8

Arming theory for licensing?

Answer 8

Arming, NK cells intrinsically hyporesponsive, and inhibitory signalling will ‘arm’ and increase their capacity for activation.

Question 9

Disarming theory for licensing?

Answer 9

NK cells are intrinsically hyperresponsive, and inhibitory signalling will dampen their responsiveness.

Question 10

Rheostat theory for licensing?

Answer 10

Intrgration of signals for multiple of NK receptors to determine their competency.

Question 11

What things may affect/explain licensing?

Answer 11

DIfference between ITAM and ITIM signalling.

Or licensing induces clustering of inhibitory and activating receptors.

Question 12

Some HLA-A types are associated with poorer HIV prognosis, why might NK licensing explain this?

Answer 12

HLA-A increases the number of signal peptides that can be expressed by HLA-E and recognised by NKG2A (inhibitory receptor).
However, moving balance away from inhibitory KIRs to inhibitory NKG2A can reduce the potency of NK cells.

Question 13

Why might expansion and adaptive NK cell therapy of allogeneic as well as autologous NK cells work?

Answer 13

Because autologous NK cells may be incompletly inhibited- greater activation and anti tumour killing.

Question 14

What problems might you have to overcome?

Answer 14

How to traffic and home NK cells, and overcome tumour microenvironment and immunosuppression.

Question 15

Could you use immortal NK cell lines?

Answer 15

Potentially yes, rarely turn oncogneic and if they did not so many clinical complications.

Question 16

Problem with using IL-2 to expand them?

Answer 16

Can also end up expanding Tregs.

Question 17

How to make NK cells more potent for tumour therapy?

Answer 17

Reudce their inhibitory receptors and increase activatory receptors.
Can do this with GE, or with immunomodulatory drugs.
Use in conjunction with checkpoint inhibitors.

Question 18

How could therpeutic antibodies work in conjucntion with NK cells?

Answer 18

Therapeutic antibodies against TAs could increase ADCC.

Could block NK inhibitory receptors.

Question 19

How might binding of soluble MICA/B help NK cell therapy?

Answer 19

Mops up soluble MICA/B which chronically has caused NKG2D downregulation. And will bind to MICA/B expressed on suppressive myeloid cells.

Question 20

CAR NK Cells?

Answer 20

Create activatory receptors coupled with multiple activatory domains e.g. of different activator molecules and adaptor molecules.
Overcomes inhibitoin.

Question 21

How might bi/tris specific Ab and Il-2 mutants help NK cell activation?

Answer 21

bi specific Ab can agonise NK activaory receptors and bring into contact with TAs.
IL-2 mutants that only bind high affinity IL2aBy receptor.

Question 22

What are CD25 and CD122?

Answer 22

They are the IL-2a and IL15 B receptor.

Question 23

Tissue specific NK cells are also found where? 3 examples?

Answer 23

Uterus, spleen and liver.

Question 24

Phenotype of unique NK T cells in the uterus?

Answer 24

CD56high CD16- and CD94/NKG2A+

Question 25

What are uterine NK cell recptor profiles like?

Answer 25

Many activating recepotrs, and many KIR recepotrs, especially those that recognise HLA-C.

Question 26

What kind of cytokines might NK cells produce? And what might their function be?

Answer 26

Produce IFN-y and other tissue remodelling factors like EGF and Ang 1+2. Important for extravillous trophoblast invasion of the spiral arteries.

Question 27

What are changes in uterine NK cells associated with?

Answer 27

Associated with recurrent miscarriages, pre-eclampsia and endometriosis..

Question 28

What do CD94/NKG2A and LILRB1 receptors on uterine NK cells bind to and do?

Answer 28

NKG2A will bind to HLA-E, thought to prevent NK killing. | LILRB1 binds to HLA-G dimers, might be important for tolerogenic effects.

Question 29

How might changes in NK cells affect endometriosis?

Answer 29

Changes may affect the abiliity of cytotoxic NK cells to remove ectopic endometrium.

Question 30

What two KIRs are associated with improved with slower progression of HIV in patients with HLA-B w4lso80 allotype?

Answer 30

Both KIR 3DRS1 and the inhibitory receptor KIR 3DL1 bind this HLA allele. How higher expression of the stimulatory receptor helps mechansitcally not so clear (education or elimination) The high binding of inhibitory KIR 3DL1 is thought to help increase hyperresponsiveness post licensing.

Question 31

Are activatory KIRs associated generally with good outcomes in cancer and infection?

Answer 31

Associated with bad outcomes in cancer, but good outcomes in infection, though mechanisms not understood!

Question 32

How does CMV avoid NK cell activation?

Answer 32

Produces lots of decoy MHC 1 like receptors like UL18, which also associates with B2m. Can produce UL40, which is cleaved in membrane and loaded onto HLA-E to replace the leading sequence that is no longer loaded due to TAP inhibition.

Question 33

How does HIV evade NK cells?

Answer 33

Stimulation of both activatory recepotrs NKG2D and NTB-A is required for activation. Vpu from HIV will remove the NTB-A ligand (NTB-B) from surface.

Question 34

What are the indications that NK cells can have 'memory'

Answer 34

Some NK cells undergo epigentic modifications following infection. NK cells can undergo T cell like expansion and contraction. Persist in higher frequencies and self renew post infection. Phenotypically they resemble T cells markers. element of antigen specificity.

Question 35

Memory group of NK cells in mice?

Answer 35

The Ly49H group which recognises CMV antigens. ONly present in mice infected with CMV.

Question 36

What memroy cell gropu of NK cells do humans show? | Who are they seen in?

Answer 36

NKG2C+ activatory HLA-E receptor. Recognise the CMV loaded UL40 leading sequence. Only seen in people seropositive for CMV.

Question 37

What changes in memory cells are seen upon PLZ4 silencing?

Answer 37

Generally downregulation of adaptor molecules important for especially activatory signalling. e.g. FcERy signalling downregulated. Attenuates SLAM and other activatory receptors. May push towards CD16 ADCC signalling. Reorganisation of receptor repertoire.

Question 38

What other epigenetic changes in NK memory cells?

Answer 38

hypomethylation of IFN-y and TNFa, faster and greater cytokine expression upon stimulation. The epigenetic changes are heterogeneous amongst memory NK cells.

Question 39

May also find CD56 negative cells, when NK cells lose their expression. Does this have functional effects?Who are they found most in?

Answer 39

Decreases their functionality | Those with chronic infections, ageing people.

Question 40

What other strange population of NK cells seen?

Answer 40

NKp46 high NK cell population, also in chronic infection. May be good for infections, but predictors of failure to IFN-y therapy.