Cytokines

Question 1

Briefly describe the key properties shared by most cytokines.

Answer 1

• low molecular weight (<30kd) proteins or glycoproteins
• synthesised in active & inactive forms
• Rapid secretion > respond immediately
• Brief: very short half-life & only released when needed > regulated to prevent harm to body
• Active @ low [ ] (bc receptors have Hi affinity=sensitive)

Question 2

discoveries of cytokines

Answer 2

1. IFN
2. Lymphokines
3. Cytokines
4. IL
5. Chemokines

Question 3

4 Cytokine functions

Answer 3

1. Pleiotropic: multiple effects on multiple cell types
2. Redundant: several cytokines can perform same function
3. Synergistic: combined (effect of 2+) => sum of individual effect
4. Antagonistic: regulatory by inhibiting activity when necessary

Question 4

Name two pro-inflammatory cytokines (+1)

Answer 4

1. IL-1
2. Tumor necrosis factor - alpha (TNF-a)
   (3. ) IL-6

Question 5

Name an anti-inflammatory cytokine

Answer 5

transforming growth factor-beta (TGF-B)

Question 6

How do CD4+ Th0 cells differnetiate into CD4+ Th1 & CD4+ Th2 cells

Answer 6

=> Th1 due to IL-2, IFN-gamma,

=> Th2 due to IL-4, IL-5

Question 7

Functions of CD4+ Th1 & CD4+ Th2 cells

Answer 7

• Th1: T cell & macrophage activation, delayed hypersensitivity
• Th2: help produce Ab (IgE, IgG2a), eosinophil & mast cell production

Question 8

Define autocrine, paracrine, endocrine

Answer 8

A: secreted by cell & affects the cell
P: targets cells nearby
E: travels through blood to get to distant cells

Question 9

signal transductiokn of cytokine receptors are positively mediated by: (2)

Answer 9

• JAK (Janus Kinase) > bring alpha & beta units closer

- STAT (signal transducer & activators of transcription) > phosphorylate

Question 10

effects of chronic Th1 stimulation via STAT 1

Answer 10

• chronic inflammation

- auto immune disease : Type 1 diabetes; MS; Crohn’s disease

Question 11

effects of chronic Th2 stimulation via STAT 6

Answer 11

• allergy

- fail to respond to infection