Innate Immunity

Question 1

Describe the innate response

Answer 1

• Localised in tissue

- Rapid immediate response

Question 2

What are the advantages of innate response?

Answer 2

• first line of defence
• immediately active
• can recognise and destroy a large number of pathogens

Question 3

What are the disadvantages of innate response?

Answer 3

• Not specific
• Not highly effective overall
• Does not have immuniologi.c memory

Question 4

What are the stages of innate immunity?

Answer 4

• Recognition (determining self from non-self)
• Effector triggering (targeting a response to the right place at the right time)
• Resolution (regulating the reaction, to avoid bystander activation)
• Memory (mounting a stronger, faster response second time around)

Question 5

What is the first line of defence?

Answer 5

• Skin- slightly acidic, which is useful as microbes tend to prefer more alkaline/neutral environments
• Mucosal membrane

Question 6

What happens when exposed to bacteria? when dendritic cells arrive at site

Answer 6

• 0-4hours
• • Macrophages and dendritic cells arrive at site, macrophages engulf bacteria, dendritic cells link between innate and adaptive immunity and enter lymph
• Take up the phagocytose bacteria and kills it which activate cell cascade

Question 7

What happens when exposed to bacteria? after dendritic cell action

Answer 7

• Blood vessel walls increase in permeability as macrophages secrete cytokines that attract other cells (IL-6, IL-6 and TNF-a)
• Macrophages also secure histamine, prostaglandins and leukotrienes

Question 8

Describe soluble mediators

Answer 8

• Complement
• Plasma proteins c1-C9
• Activated by extracellular pathogens
• Promote inflammation
• Act as enzymatic cascade, producing effector molecules involved in inflammation (C3a and C5a), phagocytosis (C3b) and cell lysis (C5b-9)

Question 9

Describe the recruitment of cells

Answer 9

• Neutrophils (many can be produced) phagocytose bacteria with help of complement (C3a and C5a stick to tissue which shows neutrophils where to go)
• Monocytes differentiate into macrophages (cytokine GMCSF helps this stimulation)
• Bacteria are reproducing very rapidly, e.g. tetanus