Innate immunity: ILCs and NK cells + Review

Question 1

What are nk cells

Answer 1

Innate lymphoid cells = ilcs

Question 2

What do nk cells share

Answer 2

Progenitor = common lymphoid progenitor with b and T cells
But nk cells = innate immune cells, but b and T cells = adaptive
Nk cell = most abundant ilc

Question 3

Describe ilcs and nk cells

Answer 3

Derived from common lymphoid progenitor
Not antigen specific = provide innnate immunity, not specific to epitope

Question 4

How many types of ilcs

Answer 4

3

Question 5

What determines what ilc generates into

Answer 5

Cytokines can influence which ilc to generate into
Which cell the precursor differentiates into

Question 6

Describe ilcs - reside

Answer 6

Tend to reside in tissues = important in mucosal immunity, fight against pathogens

Question 7

Describe ilcs - contribute

Answer 7

To defuse against specific microbes

Question 8

Describe ilcs - research

Answer 8

Very active area of research

Question 9

Where are nk cells found

Answer 9

In tissues or circulation

Question 10

What leads to differentiation into diff ilcs

Answer 10

Diff inducing cytokines lead to differentiation into diff ilcs = secrete diff cytokines

Question 11

All ilcs are produced in same amount in response to all infection?

Answer 11

May need more of one type of ilc = depnds on infection

Question 12

What does ilc1 do

Answer 12

Induce differentiation into ilc12, and produce fin-gamma = effector molecule
Mostly = defense against viruses, intracellular pathogens

Question 13

What does ilc2 do

Answer 13

Expulsion of extracellular parasites

Question 14

What does ilc3 do

Answer 14

Immunity to extracellualr bacteria and fungi

Question 15

What cells have prrs

Answer 15

Nk, t, b, all myeloid
But ilcs = group 1,2,3 = do not have prrs

Question 16

Describe innate lymphoid cells- take home

Answer 16

Act in tissues
Activated by cytokines produced by dendritic cells or other cells (epithelial cells)
Secrete cytokines that contribute to Pathogen killing

Question 17

Describe innate lymphoid cells- pic

Answer 17

Gut mucosa
Activated dendritic cell produce cytokine, that activates ilc = clear intracellualr pathogen
Epithelial cells secrete cytokiens then activate ilc2 - then more cytokiens —> goblet cells clear parasitic infection
Paneth cells clear extracellalr bacteria and fungi

Question 18

Are all ilc cells tissue resident

Answer 18

Nooo
Ilc2 can circulate

Question 19

Describe research data - ilcs

Answer 19

Immunofluroescent staining of mouse ilea = part of gut
Mice untreated = control
Mice treated = with il-25 = cytokien produced during helminth parasitic infection
= more ilc cells and some in lymphatic vesssels = ilcs circulate

Question 20

What are conclusions of research of ilcs

Answer 20

New knowledge constantly changes understanding of immune system
Ilc2 = not solely tissue resident = can travel in some cases

Question 21

What are nk cells

Answer 21

Lymphoid cells with innate immune functions

Question 22

What do nk cells express

Answer 22

Receptors for self proteins that can be induced by infections, malignant transformations (cancer tumours) and other stresses

Question 23

What can activated nk cells do

Answer 23

Kill altered self cell (directly kill host cells)—> due to infection or tumour cells
Produce cytokines that induce adaptive responses against the altered self cell, help differentiation of T cells

Question 24

Describe nk cell receptors - gen

Answer 24

Germaine encoded = do not change,innate immune cells = receptors the same
Have 2 receptors = activating and inhibitory receptors

Question 25

What do nk cell receptors recognize

Answer 25

Mhc class one molecules or mhc class 1 like molecules
Mhc class one molecules expressed on all nucleated cells = all host cells can express this

Question 26

What does nk cell have to do

Answer 26

Interpret variety of signals, determine if kill cell or not

Question 27

Describe nk cell = normal context

Answer 27

Nk cell receives activating and inhibitory signal = inhibitory signal prevents activation of nk cell
Mhc class 1 binds inhibitory receptor, activating ligand binds activating receptor on nk cell, self proteins expressed on cel surface
If have both receptors = inhibitory wins = do not kill cell

Question 28

Describe nk cell = disease context 1 - gen

Answer 28

Altered self cell does not trigger inhibitor receptor = nk cell receives only activating signal = nk cell kills target cells via granules that trigger apoptosis, creates holes/pores in target cells = leads to cell death

Question 29

Describe nk cell = disease context 1- pic

Answer 29

Virus prevents cell from presenting peptide on Mhc class 1 or conformation diff
No inhibitory signal
= only positive signals so kills cell

Question 30

Describe nk cell = balance, another way

Answer 30

Details unclear but overall balance of signalling by these receptors determines whether an nk cell kills target cell
Balance = if more activating = kill, if both = normal, if missing self = kill

Question 31

Describe nk cell = disease context 2- gen

Answer 31

Nk cell can trigger apoptosis in target cells that express a specific reactor = dr4/dr4 that bind to trail on nk cells = target dies by apoptosis triggered by signalling from this receptor binding

Question 32

Describe nk cell = disease context 2- pic

Answer 32

Activated nk cells express trail = death receptor
Dr4/dr5 expressed, some v stressed cells express ligand for trail
Once bound = nk cells start intracellular signalling and caspase 8 activated = programmed cell death, target cell programs own cell death (not Like cell death from granules)

Question 33

What can nk cells do

Answer 33

Directly kill infected cells