Principles - Innate Immune System 1) Leukocytes

Question 1

What are the 3 main functions of the innate immune system.

Answer 1

• identification of microorganisms
• rapid destruction and clearance
• stimulation of adaptive system

Question 2

What is the main target of neutrophils?

Answer 2

bacteria and fungi

Question 3

What are the main functions of eosinophils?

Answer 3

target large parasites and modulate allergic responses

Question 4

What do basophils and mast cells do?

Answer 4

release histamine for inflammatory responses

Question 5

Which out of basophils and mast cells leaves the bone marrow already mature and which circulates in an immature form (only maturing once in a tissue site)?

Answer 5

basophils leave bone marrow already mature

mast cells circulate immature

Question 6

What do B lymphocytes do?

Answer 6

release antibodies

assist in T cell activation

Question 7

What are NK cells?

Answer 7

virus infected and tumour cells

Question 8

What do macrophages do?

Answer 8

phagocytosis

stimulate lymphocytes and other immune cells

Question 9

What do dendritic cells do?

Answer 9

act as antigen-presenting cells, activating T lymphocytes

Question 10

Which lymphocytes are linked to asthma and allergy?

Answer 10

eosinophils

Question 11

What are the first line of defence against bacteria/fungi?

Answer 11

phagocytes

Question 12

Where do neutrophils and monocytes carry out phagocytosis?

Answer 12

circulation

Question 13

Where do macrophages and dendritic cells carry out phagocytosis?

Answer 13

tissues

Question 14

What are polymorphonuclear cells?

Answer 14

neutrophils

Question 15

What is the leukocyte largest in number?

Answer 15

neutrophils

Question 16

Do neutrophils circulate freely in the blood?

Answer 16

Yes

Question 17

What are the first line of defence at sites of damage or infection?

Answer 17

neutrophils

Question 18

What are circulating monocytes precursors of?

Answer 18

tissue macrophages

Question 19

Where are monocytes and macrophages produced?

Answer 19

bone marrow

Question 20

Do dendritic cells phagocytose as immature or mature cells?

Answer 20

immature

Question 21

When do dendritic cells start to mature?

Answer 21

as they respond to inflammatory indicators

Question 22

What happens to dendritic cells as they start to mature?

Answer 22

lose phagocytotic activity, migrate to lymph nodes, present antigen to T lymphocytes

Question 23

What do phagocytes produce?

Answer 23

cytokines

Question 24

Are macrophages destroyed during phagocytosis?

Answer 24

No

Question 25

What are used to recognise pathogen associated molecular patterns?

Answer 25

pathogen recognition receptors

Question 26

What are PAMPs?

Answer 26

pathogen associated molecular patterns - expressed by microorganisms, but not by human cells

Question 27

What is the PAMP in bacterial loppolysaccharides?

Answer 27

binds to toll-like receptor 4, which is a Pathogen recognition receptor expressed on macrophages and dendritic cells

Question 28

What do opsonins do?

Answer 28

act as a bridge between the pathogen and the phagocyte receptors, facilitating uptake of microorganisms

Question 29

What are the main opsonins?

Answer 29

Fc fragment of IgG C3b Collectins

Question 30

What is C3b?

Answer 30

fragment of C3 generated by compliment activation

Question 31

What are collectins?

Answer 31

plasma proteins that bind to microbial cells walls

Question 32

What are microorganisms coated with to facilitate phagocytosis?

Answer 32

proteins e.g. acute phase proteins, antibodies and complement proteins

Question 33

What type of protein is C reactive protein?

Answer 33

acute phase protein

Question 34

What are the two types of killing in phagocytosis?

Answer 34

oxidative and non oxidative

Question 35

What is oxidative killing especially important for?

Answer 35

neutrophils

Question 36

What crucial enzyme is involved in oxidative killing?

Answer 36

NADPH oxidase complex

Question 37

What does NADPH oxidase complex do?

Answer 37

converts oxygen into reactive oxygen species - hydrogen peroxide, superoxide 02 and hypochlorite H0Cl, which are lethal to microorganisms

Question 38

What does non oxidative killing involve?

Answer 38

Can kill bacteria inside cell and in local environment | Bacteridical enzymes released e.g. defensins, lysozomes, collagenase and lactoferrin

Question 39

What does lactoferrin do?

Answer 39

collect iron as lots of bacteria depend on iron for their metabolism

Question 40

Where are the bactericidal enzymes made?

Answer 40

in lysosomes and neutrophil secondary granules

Question 41

What does phagocytosis do to neutrophils?

Answer 41

glycogen reserves are depleted, neutrophils die, formation of pus occurs

Question 42

What do primary granules of neutrophils do?

Answer 42

kill ingested microbes, digest their remains. Granules fuse with phagoctyic vesicles containing enzymes

Question 43

What are ensymes like myeloperoxidase very good at generating?

Answer 43

free radicals

Question 44

What is movement toward or away from a chemical stimulus called?

Answer 44

chemotaxis

Question 45

What happens in patients with phagocyte deficiencies?

Answer 45

reccurent deep bacterial and fungal infections, often poorly responsive to antibiotics