Lecture 18

Question 1

What is the role of the innate responses in combating infection in bacterial infections?

Answer 1

1. deliver more cells and more effector molecules to the site of infection
2. induce blood clot to prevent spread of infection
3. promote repair to the injured tissue

Question 2

What are the two phases of the innate response?

Answer 2

early: preformed effector molecules (complement) and innate immune cells
induced: pro-inflammatory cytokines produced by macrophages, leukotrines and prostaglandins

Question 3

What are defensins?

Answer 3

small cationic amphipathic peptides that are secreted by various cells
- they disrupt the bacteria’s cytoplasmic membrane

Question 4

What is lysozyme?

Answer 4

an antimicrobial protein secreted into saliva and tears
- causes bacteria to rupture from osmotic pressure by cleaving the glycosidic bonds of peptidoglycan

Question 5

What is the role of C3b in the complement cascade?

Answer 5

C3b binds to the pathogens’ surface, can also be an opsonin

Question 6

How do mast cells release histamine etc?

Answer 6

they have TLRS and receptors for c3a and c5a

Question 7

What PRRs recognize structures on gram pos/neg bacteria?

Answer 7

TLR, NOD1, NOD2

Question 8

What are the four things that happen in the induced phase of the innate immune system?

Answer 8

1. neutrophils and monocytes are recruited to infection sites
2. Acute phase response
3. Phagocytosis and phagosome maturation (both resident and recruited cells)
4. alternate ways that neutrophils can kill pathogens