Lecture 2

Question 1

What are the four main elements of the vertebrate immune system?

Answer 1

Complement mediated cell killing
Antimicrobial peptides
Cell mediated killing
Antibody production

Question 2

What cells of the innate immune system commonly provide the first line of defense in infections?

Answer 2

Macrophages and neutrophils

However if these are not capable of clearing the infection then adaptive immune response may develop in 4-7 days

Question 3

How common is an immune system through evolutionary time?

Answer 3

All multicellular forms of life have a mechanism to distinguish self from non-self to allow attacks to be targeted at pathogens
Almost all organisms have some form of an immune system as there is a large selection pressure to resist pathogenic infection

Question 4

Where was the innate immune system discovered?

Answer 4

In drosophila with the discovery of pattern recognition receptors (TLR) and the signalling pathway leading to NFkB activation

Question 5

What are the general principals of the innate immune system?

Answer 5

Frontline host defense which alerts the adaptive immune system to the pathogen invasion
Pattern Recognition through the toll like receptor and the ancient toll receptor pathway
Complement system
Induced innate responses to infection

Question 6

What are the three general features of innate immunity?

Answer 6

Phagocytosis where pathogens, or their components are engulfed by pathogen recognition receptor bearing leukocytes
Target cell lysis where cancer cells and infected cells express surface molecules marking them for immune destruction
Inflammation when leukocytes phagocytose foreign material they produce cytokines promoting wound healing and attracting further leukocytes

Question 7

Why might antimicrobial peptides be the most ancient immune defense?

Answer 7

They are found in both plants and animals, often with similar protein structures suggesting that they may have developed before the evolutionary division between animal and plant cells