T cells: cytokine patterns, cross regulation, receptors, homing

Question 1

Describe polarizing cytokines

Answer 1

Polarizing cytokines are secreted by dcs and neighbouring innate and adaptive immune cells
Tells T cell which to become

Question 2

What do polarizing cytokines do

Answer 2

Activates diff stat proteins within each cell

Question 3

When Th1 response

Answer 3

When infections by viruses and intracellualr pathogens

Question 4

When Th2 response

Answer 4

When parasites and other extra cellular pathogens - also allergy

Question 5

When Th17 response

Answer 5

Infections by extracellular bacteria and fungi - also in autoimmunity

Question 6

When Tfh response

Answer 6

Activating B cells in lymph node

Question 7

Are all cd4+ T cell subsets always active

Answer 7

Noooo
Cell mediated response is dominated by one of the T cell subsets - will have others but one dominates

Question 8

What is activated when viruses and intracellular pathogens

Answer 8

Ctl
Th1

Question 9

What is activated when helminths and extra cellular pathogens

Answer 9

Th2

Question 10

What is activated when extra cellular bacteria and fungi

Answer 10

Th17

Question 11

What types of cells does th1 target

Answer 11

Macrophages

Question 12

What types of cells does th2 target

Answer 12

Eosinophil, mast cell, basophil

Question 13

What types of cells does th17 target

Answer 13

Neutrophils

Question 14

Cytotoxic T cells - effector molecules and cytokines

Answer 14

Perforin
Granzyme b
Fas ligand
Infy - type 2 ifn

Question 15

Th1 cells - effector molecules and cytokines

Answer 15

Ifny
Cd40 ligand
Fas ligand

Question 16

Th17 cells - effector molecules and cytokines

Answer 16

Il-17
Il-22
Cd40 ligand

Question 17

Treg cells - effector molecules and cytokines

Answer 17

Il-10
Tgf-beta

Question 18

Describe cross regulation - gen

Answer 18

Combo of diff T cells but one more dominant
Effector cytokines help reinforce the predominant subtype they are part of

Question 19

Name specifically what happens when cross regulation

Answer 19

2 patterns cross regulate
Th2 secretes I’ll-4 = inhibits th1 differentiation
Th1 secrets ifn-y = Inhibits th2 proliferation
Il-4 or ifn-y inhibits th17
MAKES SURE ONE DOMINATES

Question 20

Describe th1/th2 cross regulation

Answer 20

MASTER TRAscnriptional regulators commit T cells to one subset or the other

Question 21

How does th1 regulated th2

Answer 21

Il-12—> stat4 —> t bet
Suppresses gata3
Increases ifn-y (effector cytokine)
But suppress il-4, Il-5=th2 effector cytokines
= promotes th1
(Tbet suppresses th2 pathway gene expression)

Question 22

How does th2 regulate th1

Answer 22

Il-4 —> stat6 —>gata3
Inhibit t bet, and ifn-y
But promote il-4, Il-5 = promotes th2
(Gata3 suppresses th1 pathway gene expression)

Question 23

Describe decision between th17/treg - gen

Answer 23

Tgf-b is a key cytokine for differentiation of both subsets

Question 24

Describe decision between th17/treg - what helps decide

Answer 24

Il-6 = switch = induces th17 subset differentiation instead
Depends on environment
Balance between 2 is ideal, depends on what is needed - beneficial outcomes of each

Question 25

What favours Treg instead of th17

Answer 25

Normal state favours development of itreg population to keep inflammation down

Question 26

What favours th17 over treg

Answer 26

Infection = lead to Il-6 production = would stimulate more antibacterial th17 differentiation

Question 27

Where do these cells exert their effector function

Answer 27

Polarizing cytokines impact differentiation of T cells - signal 3, effector cytokines are produced by differentiated T cells —> th1, th2, th17 = Leave lymph node and migrate to site infection, To repsond to infection Tfh = stay in lymph node and activate B cells

Question 28

What are cell surface molecules

Answer 28

Different cell surface molecules are expressed by naive vs effector T cells since they travel to different locations in body

Question 29

What do effect T cells express

Answer 29

Effector T cells express molecules that target them to specific tissues - like skin vs gut = depends on site of infection Diff adhesion molecules

Question 30

What determines where effector T cells travel

Answer 30

Partly determined by which lymph node they get activated - if activated in lymph node that drain skin = effector T cells will upreg homing molecules that send them to the skin Depends on which lymph node

Question 31

Effector cytokines patterns—>

Answer 31

Tied to function

Question 32

Describe decision point

Answer 32

Addition of diff cytokines can switch induction of one T cell subset over another like treg and th17

Question 33

Summarize homing

Answer 33

Tissue specific molecules target effector T cells to diff tissues Naive vs effector T cells have some Differenet adhesion molecules

Question 34

Th1 signal 3 polarizing cytokine

Answer 34

Ifn-y and Il-12

Question 35

Th1 effector cytokine

Answer 35

Ifn-y

Question 36

Th1 master transcriptional regulator

Answer 36

T bet

Question 37

What does th1 do

Answer 37

Macrophages activation - that has persistent infection Activation and differentiation of naive cytotoxic T lymphocyte precursors into effector ctl - through cd40L binding - licence dcs

Question 38

What does th1 respond to

Answer 38

Intracellular pathogens - like intracellular bacteria - m tuberculosis and salmonella Intracellular parasites - leishmania and toxoplasma and viruses

Question 39

Th1 tfs activated

Answer 39

Stat 1 and stat 4 proteins get activated = phosphorylated

Question 40

What does th1 secrete

Answer 40

Infy at point of interaction

Question 41

Th1 functions - gen = secrets, targets, aids

Answer 41

Targets macrophages - th1 cell tcr recognizes pmhc-2 on macrophage surface To aid in killing of microorganisms that persist in macrophages vesicles

Question 42

Th2 cells - effector molecules and cytokines

Answer 42

Il-4 Il-5 Il-13 Cd40 ligand