Cells of the Immune System

Question 1

What is the function of phagocytes?

Answer 1

• First line of defence
• Remove extracellular debris

Question 2

Give 2 examples of mammalian phagocytic cells

Answer 2

• Macrophage
• Neutrophils

Question 3

Where are macrophages usually located?

Answer 3

They are usually tissue resident

Question 4

Where are neutrophils usually located?

Answer 4

The blood

Question 5

What is the precursor for macrophages?

Answer 5

Monocytes

Question 6

Give examples of important pattern recognition receptors

Answer 6

• Mannose receptors
• Scavenger receptors
• Toll like receptors

Question 7

What chemicals do phagocytes use to kill ingested bacteria?

Answer 7

• Free radicals
• Acid
• Nitric Oxide
• Enzymes

Question 8

What does the mannose receptor detect?

Answer 8

Sugars pn the surface of many bacteria and some viruses

Question 9

Do macrophages have Fc receptors?

Answer 9

Yes

Question 10

What are the differences between neutrophils and macrophages?

Answer 10

Neutrophils are found in the blood and macrophages in the tissues, neutrophils are much shorter lived than macrophages

Question 11

What kind of pathogens are eosinophils responsible for fighting?

Answer 11

Large extracellular pathogens e.g. parasites

Question 12

How are eosinophils activated?

Answer 12

By Fc receptors

Question 13

Why does it not matter than activation of eosinophils take a few days?

Answer 13

Parasites grow more slowly than other pathogens

Question 14

How do eosinophils kill parasites?

Answer 14

They release enzymes and toxic proteins onto the parasite

Question 15

What is the role of mast cells?

Answer 15

Recruit additional immune cells to the site of infection

Question 16

What do mast cells do in response to pathogens?

Answer 16

Release inflammatory mediators into the tissue

Question 17

Give a similarity between mast cells and eosinophils

Answer 17

They are both activated in the same way

Question 18

What kind of pathogens do natural killer cells deal with?

Answer 18

Intracellular pathogens such as bacteria and viruses, they also kill tumour cells

Question 19

What kind of cells are innate anti-viral/anti-tumour cells?

Answer 19

Natural Killer cells

Question 20

What type of cells are adaptive anti-viral cells?

Answer 20

Cytotoxic T cells

Question 21

How do natural killer cells kill cells?

Answer 21

They release granules containing perforin and granzymes

Question 22

How do granzymes kill cells?

Answer 22

They stimulate apoptosis

Question 23

How are NK cells activated?

Answer 23

• In infected cells MHC class 1 expression is downregulated
• Cells undergo stress causing stress protein to be produced on surface
• This prompts NK cells to be switched on

Question 24

What is the function of dendritic cells?

Answer 24

Main cell type to mediate T cell activation

Question 25

How do dendritic cells mediate T cell activation?

Answer 25

• Activated by pattern recognition receptors at site of infection
• Travel to lymph nodes
• Activate naive T cells in LN