Innate Immune Response

Question 1

The innate immune system responds to invading pathogens immediately upon contact.
What humoral and cellular responses does it involve?

Answer 1

1. Complement activation (blood plasma)
2. Phagocytosis by macrophages and neutrophils
3. Natural killer cells

Question 2

What are the functions of the complement system?

Answer 2

1. Produces Membrane Attack Complex (MAC) to ‘stab’ invading pathogens.
2. Produces anaphylatoxins
3. Primes pathogens for phagocytosis by macrophages and neutrophils.
4. Attracts neutrophils to the site of infection.

Question 3

What are the 3 main pathways of complement activation?

Answer 3

1. Classical pathway
2. Lectin / mannose-binding pathway
3. Alternative pathway

All pathways involve the activation of complement factors C3 & C5