Other T helper effectors: TH17, induced Treg, and TFH

Question 1

IL-22 source and function

Answer 1

TH17 effectors, induce epithelial cells to produce antimicrobial peptides, increases epithelial cell turnover.

Question 2

iTreg is a form of…

Answer 2

Peripheral tolerance

Question 3

Type-3 response driver and function

Answer 3

FH17 effectors, activation of antimicrobial functions of epithelium and neutrophils

Question 4

Linked recognition or cognate interaction

Answer 4

A B-cell and a TFH cell recognize different epitopes of the same antigen and form cognate pair through TCR:MHCII, CD40:CD40L and ICOS-L:ICOS

Question 5

TFH differentiation reguires

Answer 5

Cytokines (IL-6, IL-21) and co-stimulatory molecule (ICOS-L)

Question 6

Cognate pair: CD40L source and function

Answer 6

TFH, activate B cells

Question 7

ICOS-L is expressed by…

Answer 7

Professional Ag-presenting cells (and B-cells?)

Question 8

Induced Treg function

Answer 8

Immunosupression; soaks up IL-2 and B7 from APCs and express CTLA4, IL-10 and TGF-β

Question 9

Cross-regulation: TH1 differentiation is inhibited by:

Answer 9

IL-4 (and Treg cells)

Question 10

Retinoic acid and TGF-β induce…

Answer 10

iTreg

Question 11

Late infection: antigen wanes and IL-6 drops, which means…

Answer 11

That Tregs take over and TH1 and TH2 differentiation again is inhibited.

Question 12

TH17 function

Answer 12

Driving type-3 inflammation

Question 13

Cross-regulation: TH17 differentiation is inhibited by:

Answer 13

Both IL-4 and INF-γ

Question 14

Cognate pair: IL-21 source and function

Answer 14

TFH, triggers of B-cell proliferation.

Question 15

Cytokines that directs isotype switching are

Answer 15

TGFβ, IL-4 or IFNγ

Question 16

Fate specifying cytokines in mucosal tissue with PAMPs

Answer 16

TGF-β, IL-6, IL-23

Question 17

Major T effectors in mucosal tissue

Answer 17

TH17 and iTreg

Question 18

Difference between Treg and iTregs

Answer 18

Treg differentiation in thymus, iTreg in secondary lymphoid tissues.

Question 19

TGF-β, IL-6, IL-23 induce…

Answer 19

TH17

Question 20

IL-17 source and function

Answer 20

TH17 effectors, induce epithelial cells to produce antimicrobial peptides, activate stromal and myoloid cells to produce G-CSF, which stimulate neutrophil production and activate stromal cells and epithelial cells to produce chemokines that attract neutrophils.

Question 21

CCL20 source and function

Answer 21

TH17 cells, chemoattraction of FH17 cells.

Question 22

T cell activation in mucosae means that..

Answer 22

…the T-cells will patrol mucoase by binding of MadCAM-1 (blood vessels), CCL25 (epithelial cells) and E-cadherin.

Question 23

What decides which isotype specifying chemokine TFH effectors will produce?

Answer 23

Cytokine microenvironment around TFH when it was activated by dendritic cell in phase 1.

Question 24

Fate specifying cytokines in mucosal tissue without PAMPs

Answer 24

Retinoic acid and TGF-β

Question 25

Cross-regulation: TH2 differentiation is inhibited by:

Answer 25

INF-γ (and Treg cells)

Question 26

Phases in TFH activation:

Answer 26

1. Naïve T-cells are activated on dendritic cells in T-cell area, becomes pre-TFH cells
2. Migration of pre-TFH cells towards CXCL13 in B-cell area due to CXCR5.
3. Activated B-cells form cognate pair with pre-TFH cells, where ICOS-L from B-cells and IL-21 from T-cell finishes differentiation.

Question 27

Cognate pair: IL-5, IL-6 source and function

Answer 27

TFH, triggers differentiation into plasma cells.

Question 28

Isotype switching is directed by…

Answer 28

Cytokines produced by TFH effectors

Question 29

Defining transcription factor induced by IL-21

Answer 29

Bcl-6

Question 30

Early infection: differentiation of T effectors to TH17 instead of iTreg means…

Answer 30

That inhibition by Tregs of TH1 and TH2 differentiation is lifted, which results in TH17 inhibition.