T cell mediated immunity I

Question 1

Sphingosine 1 phosphate

Answer 1

A lipid molecule that acts like a chemokine attracting T cells ( both naive and effector) out of lymphoid organs. It binds to the S1PR1 receptor.

There is an S1P concentration maintained such that it is at high concertation in

lymph and blood, and low cocnetration within the extravascular tissue of SLOs.

If the naive T cells are not activated after a few hours, they will express S1PR1, and will be drawn out of the lymph node into lymphatics, and back into blood

Question 2

ICOS‐L and ICOS are most important in. . .

Answer 2

T cell dependent B cell responses

Question 3

Circulation of Naive and Effector T cells

Answer 3

Question 4

B7 and CD28 family proteins

Answer 4

Question 5

Antigen recognition with and without second signals

Answer 5

Question 6

Downstream TCR signaling

Answer 6

Question 7

TCR-mediated Ca²⁺ signaling

Answer 7

Question 8

Inhibitors of calcineurin pathway

Answer 8

Cyclosporine and Tacrolimus

Cyclosporine binds to cyclophilin and tacrolimus binds to FKBP. Both complexes are inhibitors of calcineurin.

Question 9

T cell defense against intracellular pathogens

Answer 9

Question 10

The T Cell Receptor Complex

Answer 10

Question 11

T cells are of particular importance for pathogens which. . .

Answer 11

. . .survive and replicate inside of host cells

Question 12

How calcineurin mediates NFAT transcription

Answer 12

Calcineurin dephosphorylates cytosolic phospho‐NFAT, exposing a nuclear localization signal.

Question 13

Summary of T cell migration events from infection to arrival of activated T cells on site

Answer 13

Question 14

Calfineurin-NFAT pathway

Answer 14

Question 15

Primary use of cyclosporine

Answer 15

Post-transplant operation to prevent graft rejection

Question 16

Steps in T cell activation

Answer 16

Question 17

Calcineurin

Answer 17

A cytosolic serine-threonine phosphatase activated by calmodulin, which is in turn activated by Ca²⁺

Question 18

Mechanism of TCR signal transduction

Answer 18

Lck rests on CD4. When pMHCII is recognized by both CD4 and the TCR, induced proximity enables phosphorylation of the ITAMs on the TCR by Lck. The phosproylated CD3 and zeta chain ITAMs then recruit ZAP-70 via SH2 domains. ZAP-70 then autophosphorylates and activates its tyrosine kinase activity to further transduce and amplify the signal via phosphorylation of an adaptor which activates PLCγ1, PI3K, and GEFs by induced proximity and ZAP-70 phosphorylation.

Question 19

IP₃ receptor

Answer 19

Present on cytosolic side of ER. Binds to IP₃ and triggers release of Ca²⁺ into cytosol.

Question 20

What adhesion molecule contributes to naive T cell entry into lymph nodes, but not effector T cell entry into infected tissues?

Answer 20

L-selectin

Question 21

PD1 inhibitory signaling

Answer 21

Question 22

Antigen‐induced TCR signaling without B7‐induced CD28 signaling leads to. . .

Answer 22

No response, apoptosis, or anergy.

Question 23

Role of CRAC and STIM1 in IP₃→Ca²⁺ signaling

Answer 23