Lecture 10 - Activation and differentiation of CD4 + T-cells (2)

Question 1

Why do we need different subsets of CD4+ T-cells?

Answer 1

• Different pathogens need different immune responses

- Different CD4+ Th cells are needed to deal with different pathogens

Question 2

What are cytokines?

Answer 2

Small proteins released by cells that have effects on:

• Interactions between cells
• Communications between cells
• Behaviours of cells

Question 3

What are the effects of cytokines?

Answer 3

• Act on receptors

- Act on any cell that has the right receptor

Question 4

How many subsets for T helper cells are there?

Answer 4

Two

Question 5

What is the role for Th1 cells?

Answer 5

Responses with intracellular pathogens

Question 6

What is the role for Th2 cells?

Answer 6

Responses with extracellular pathogens

Question 7

What are Th1 cells characterised by?

Answer 7

The production of:

• Interleukin-2
• Interferon-gamma
• Lymphotoxin

Question 8

What are Th2 cells characterised by?

Answer 8

The production of:

• Interleukin-4
• Interleukin-5
• Interleukin-9
• Interleukin-13

Question 9

How is differentiation into a specific Th cell regulated? [3]

Answer 9

Signal 1: Antigen
Signal 2: co-stimulatory molecule
Signal 3: Cytokine signal

Question 10

How do Th1 cells down regulate the production of Th2 cells?

Answer 10

Via secretion of Interferon-gamma

Question 11

How do Th2 cells down regulate the production of Th1 cells?

Answer 11

Via Interleukin-4

Question 12

What harmful effects can come from Th cells?

Answer 12

Th1 - Autoimmunity, and transplant rejection

Th2 - Allergies, and autoimmunity

Question 13

What to Th cells do once they have matured?

Answer 13

They acquire homing molecules on their surface so they can migrate

Question 14

What do Th17 cells do?

Answer 14

Involved in regulation of immune responses at epithelial surfaces

Question 15

What is the role of T follicular helper T cells?

Answer 15

They go to germinal centres of lymph nodes and help B-cells make antibody

Question 16

What are the role of Tregs?

Answer 16

They suppress self-harmful immune responses

Question 17

What are the two ways Tregs can be formed? [2]

Answer 17

• In the thymus as part of the normal T-cell development

- Induced from naive CD4+ T-cells

Question 18

What is the role for the cytokines released by Tregs?

Answer 18

Inhibit harmful T-cells via:

• Releasing anti-inflammatory cytokines
• Outcompeting effector T-cells
• Killing self-reasctive T-cells

Question 19

Lack of Tregs causes […].

Answer 19

Autoimmune diseases

Question 20

True or False? CD4+ T-cells subsets can become other subsets.

Answer 20

• True

- It is called T-cell plasticity