T cell activation

Question 1

CD4 role in immune response

Answer 1

Help other immune cells to use an appropriate immune response

Question 2

CD8 role in immune response

Answer 2

Kill infected or stressed cells

Question 3

Brings antigen from tissue to draining lymph nodes

Answer 3

Dendritic cells

Question 4

Dendritic cell immune response in skin after sensing a threat

Answer 4

Immature: endocytosis, sensing pathogens bia PAMPs, activated: migrates and processes antigen, fully matured in lymph node: presents antigen on MHC and expresses co-stimulatory molecules.

Question 5

Cross-presentation

Answer 5

Non-infected APCs need to activate CD8 cells by presenting extracellular antigen on MHCI.

Question 6

Main role of dendritic cells

Answer 6

Presenting antigen to naive T cells

Question 7

how do T cells get into lymph nodes?

Answer 7

Either from HEV or an afferent lymphatic vessel

Question 8

LFA-1

Answer 8

Binds ICAM-1 in order to initiate diapedesis of T-cells through HEV. Also binds ICAM-1 on APCs.

Question 9

How does T-cells and APCs interact?

Answer 9

As a cognate pair, forming a immunological synapse

Question 10

p-SMAC region

Answer 10

Peripheral region of IS, contains adhesive molecules

Question 11

c-SMAC region

Answer 11

Central region of IS, contains TCR;MHC and other signaling molecules

Question 12

TCR receptor complex

Answer 12

Made up of TCR and CD3

Question 13

TCR co-receptor

Answer 13

CD4 or CD8, carries Lck

Question 14

Binding of MHC to TCR

Answer 14

CD4 brings Lck in to phosphorylate ITAMS in CD3. ITAMS in CD3 recruits ZAP-70, which causes Lck mediated phosphorylation and activation of ZAP-70

Question 15

Co-stimulation, signal 2

Answer 15

Binding of B7 to CD28 are required in addition to TCR activation.

Question 16

B7 expression

Answer 16

Are regulated such that only activated APCs are capable of co-stimulation.

Question 17

Activation signal 3

Answer 17

IL-2 cytokine are inducced by signal 1 and 2

Question 18

IL-2 receptor

Answer 18

Is expressed in a low-affinity version originally. Activation of IL-2Rα drives expression of a better receptor.

Question 19

Which is strongest, co-stimulation of CD8 or CD4 T cells?

Answer 19

CD8, often needs IL-2 from neighbouring CD4 T-cells.

Question 20

TCR activation without B7 binding leads to…

Answer 20

cell anergy

Question 21

CTLA-4

Answer 21

Binds B7 and is a checkpoint inhibitor to prevent further activation.

Question 22

Blocking checkpoint inhibitor can be medically significant because

Answer 22

It can boost T cell response.