Extracellular immunity

Question 1

Immune responses to parasitic infections are mainly … driven

Answer 1

Th2

Question 2

Where on a parasite should be targetted?

Answer 2

Weak spots e.g. digestive tract

Question 3

What are the physiological host changes induced by anti-worm immunity?

Answer 3

• Does not kill the worm but makes the GI tract inhospitable for the parasite
• Increased goblet cells resulting in increased mucin secretion, gut motility and water influx into the intestinal lumen

Question 4

Helminth infections promote the activity of which cells?

Answer 4

Antibodies
Eosinophils
Mast cells

Question 5

The choice towards a Th2 response is driven by…?

Answer 5

IL-4

Question 6

Th2 cells promote a strong antibody response based on neutralising which immunoglobulins?

Answer 6

IgG and IgE

Question 7

What is the role of mast cells in helminth infections?

Answer 7

The are the main effector in helminth immunity
Their surface is loaded with IgE and antigen binding causes mast cell degranulation resulting in inflammation which is damaging to the worms

Question 8

How do both eosinophils and masts cells have central roles in parasite immunity?

Answer 8

• Both react to antigen complexed IgE and release molecules with potent anti-worm activities.
• Mast cells stimulate worm expulsion
• Eosinophils kill worms

Question 9

List the different ways helminths can evade vertebrate immunity

Answer 9

• size
• thick extracellular coat
• molecular mimicry
• adsorbing host proteins
• surface antigen shedding
• immunosuppression
• migration

Question 10

How do Th2 cells promote neutralising antibodies?

Answer 10

• Suppress the action of macrophages

- Promote a strong antibody response based on neutralising IgGs