Lecture 11 - Differentiation and Functions of CD8 T Cells

Question 0

What activates naive T cells?

Answer 0

Dendritic cells

note; activation may include coordinated signaling (interaction of DC and T cell surface or secreting cytokines)

Question 1

What is the life cycle of T lymphocytes?

Answer 1

1. Generated in bone marrow
2. migrate to thymus
3. generation of a receptor for Ag
4. leave in naive state to populate LN
5. become activated in LN by Ags presented to them by APCs
6. activated then functional polarization

Question 2

What is functional polarization?

Answer 2

T cells take on a particular set of tasks that promote the adaptive immune response

Question 3

CD8 T cells recognize which MHC class?

Answer 3

Class I MHC associated peptides

Question 4

How are CD8 T cells activated?

Answer 4

by cross presentation mechanism of Ags

Question 5

How does CD4 help in the activation of CTLs?

Answer 5

1. produces cytokines that stimulate CTL differentiation

2. enhances ability of APCs to stimulate CTL differentiation

Question 6

What are CD8’s stimulated to differentiate into?

Answer 6

Cytotoxic T lymphocytes (CTLs) and some memory cells

Question 7

CD8 CTLs recognize Ags in the tissues and respond how?

Answer 7

by killing the target cells where the Ag is produced

Question 8

What are the two signals that lead to activation of CTLs?

Answer 8

Signal 1 = naive CD8 recognize Ags

Singal 2 = CD28-CD80 costimulation leads to proliferation and differentiation into effector CTLs

Question 9

Activated CTLs contain numerous granules called lysosomes, these contain what and what is their function?

Answer 9

perforin and granzymes, used by the cells to kill other cells

Question 10

What cytokine do activated CTLs secrete mainly, what does this cytokine do?

Answer 10

IFN-gamma; activates macrophages

Question 11

What transcriptional factor is involved with CTL differentiation? What is it’s function?

Answer 11

T-bet; regulates transcription of genes encoding perforin, granzymes and IFN-gamma

Question 12

Are CD4 helper T cells more important in generation of CD8 memory T cells or in differentiation of naive CD8 T cells to effector CTLs?

Answer 12

Generation of CD8 memory T cells

Question 13

How do CD4 helper T cells enhance activation?

Answer 13

they provide signal 3 in the form of cytokines

Question 14

APC licensing occurs when CD4 T cell recognizes what?

Answer 14

Ag presented by MHC class II, delivers activating signals through CD80/CD86 and CD40

Question 15

Activated CD4 Th cells express what? what do they bind to?

Answer 15

express CD40L; Binds to CD40 on Ag loaded DCs

Question 16

What causes APCs to be more efficient at stimulating the differentiation of CD8 T cells?

Answer 16

CD40-CD40L interaction which upregulates expression of CD80/CD86 on the APC

Question 17

What are the cytokines involved in CTL activation?

Answer 17

IL-2, IL-12, IL-15, IL-21