Mediators of Inflammation

Question 1

How is the action of inflammatory mediators tightly controlled?

Answer 1

They:

• exist as inactive precursors
• they are newly produced when induced
• they are short-lived

Question 2

What is the function of IL-1β?

Answer 2

• Activates lymphocytes
• Activates the vascular endothelium by enhancing integrin ligand expression
• So increases access of effector cells

Question 3

What is the primary function of mast cells?

Answer 3

They release histamines

Question 4

What are the effects of histamine?

Answer 4

Causes arteriolar dilation and increased vascular permeability

Question 5

Give 2 examples of vasoactive amines

Answer 5

• Histamine
• Serotonin

Question 6

When is serotonin released?

Answer 6

When platelets have aggregated

Question 7

What are the effects of serotonin in inflammation?

Answer 7

Causes vasoconstriction during clotting

Question 8

Which enzyme is responsible for the production of NO?

Question 9

What is the effect of NO in inflammation?

Answer 9

• Smooth muscle cell relaxation
• Vasodilation

Question 10

What is the role of NO in macrophages?

Answer 10

Used to breakdown substances

Question 11

Prostaglandins are metabolic products of what?

Answer 11

Phospholipids

Question 12

What inhibits the role of dendritic cells?

Answer 12

Prostaglandin 2

Question 13

Which chemical is used to synthesize prostaglandins?

Answer 13

Arachiodonic acid

Question 14

What is the role of prostaglandins?

Answer 14

They promote pain and fever

Question 15

Which enzymes are in involved in the production of prostaglandins?

Answer 15

COX

Question 16

How do steroids control pain and fever?

Answer 16

They inhibit the action of PLA₂ in making arachidonic acid

Question 17

How do NSAIDs control pain and fever?

Answer 17

They inhibit COX enzymes which prevents the production of prostaglandins

Question 18

What are the systemic mediators of inflammation?

Answer 18

• Complement system
• Clotting system
• Kinin system
• Fibrinolysis system

Question 19

What is the function of C3a and C5a?

Answer 19

• Induce mast cells to release histamine
• Act directly on blood vessels to increase vascular permeability

Question 20

What is the effect of C5a on integrins?

Answer 20

A conformational change

Question 21

What is the role of bradykinin in inflammation?

Answer 21

It is released in response to tissue damage and so links tissue damage to inflammation

Question 22

What links the complement to inflammation?

Question 23

How can tissue injury cause inflammation?

Answer 23

• Release of lysosomal enzymes
• Release of reactive oxygen species
• Release of metabolic products of arachidonic acid

Question 24

How is IL-1 secretion regulated?

Answer 24

• 2 signals are required for IL-1 to be produced
• The first signal affects gene regulation and produces an inactive precursor protein (pro-IL-1)
• 2nd signal causes activation of NLRP3 to form the inflammasome

Question 25

What is the inflammasome?

Answer 25

A protein complex which detects pathogens and stress and activates IL-1β and IL-18

Question 26

Which enzyme is responsible for the proteolytical activation of IL-1β?

Answer 26

Caspase 1