Innate Immunity

Question 1

What is innate immunity?

Answer 1

Immunity involving pretty much everything apart form lymphocytes and you have it form birth

Question 2

Is innate immunity antigen specific? What can it recognise?

Answer 2

No, can recognise PAMPs or DAMPs using PRR

Question 3

Which immune cell is particularly important in parasitic infections?

Answer 3

Eosinophils

Question 4

Which type of infection are eosinophils important in?

Answer 4

Parasitic

Question 5

Which immune cell is particularly important in releasing histamines?

Answer 5

Mast cells

Question 6

Which immune cell is particularly important in lysing infected cells?

Answer 6

NK cells

Question 7

Which two immune cells are most abundant and what %?

Answer 7

Macrophages and neutrophils (40-75%)

Question 8

What do macrophages use to recognise targets?

Answer 8

Pattern recognition receptors

Question 9

What are the three main ways the innate immunity system recognises pathogens?

Answer 9

PAMPs, DAMPs and detecting missing self

Question 10

What type of cell usually detects missing self?

Answer 10

Natural killer cells

Question 11

Which immune cells are first to the site of infection?

Answer 11

Neutrophils

Question 12

What soluble mediators do macrophages disperse?

Answer 12

Cytokines

Question 13

What type of nucleus does a neutrophil have?

Answer 13

Multilobed.

Question 14

What are primary granules of a neutrophil?

Answer 14

Sites of the enzymes that will kill phagocytksed pathogens

Question 15

What are secondary granules of a neutrophil?

Answer 15

Predominantly involved n replenishing primary granules and regulating the toxins produced during the lysis of pathogens

Question 16

What is a phagolysosome?

Answer 16

A primary granule fused with a vacuole

Question 17

What (4) steps does a neutrophil take to fight infection?

Answer 17

Move to pathogen, bind pathogen, phagocytose pathogen, and kill pathogen

Question 18

What changes integrin to a high affinity binding state?

Answer 18

Chemokine receptor activation on the neutrophil

Question 19

What helps the neutrophil roll along the surface of cells?

Answer 19

Low affinity binding of selectin

Question 20

What is diapedesis?

Answer 20

Movement of a cell across the endothelial layer

Question 21

What are the two main opsonins?

Answer 21

Antibodies and complement proteins

Question 22

What is opsonisation?

Answer 22

Coating of a pathogen with proteins to facilitate phagocytosis

Question 23

Whats the difference in antibody and complement binding?

Answer 23

Complement binds to the cell surface and antibodies bind to the receptor on the pathogen

Question 24

What are neutrophil extracellular traps (NETs)?

Answer 24

• When neutrophils become highly activated they release these nets that help trap extracellular bacteria and immobilise them

Question 25

Which are bigger, macrophages or monocytes?

Answer 25

Macrophages

Question 26

What type of receptors do macrophages/monocytes?

Answer 26

PRR's

Question 27

What do cytokines do? Where are they released from?

Answer 27

Macrophages and they recruit other cells and activate subsequent adaptive immune responses

Question 28

Why do cytokines have to be regulated strongly?

Answer 28

They have strong effects at low concentrations

Question 29

What are the 5 types of cytokines?

Answer 29

Interleukins, interferons, chemokine, growth factor and cytotoxic

Question 30

What do interferons do?

Answer 30

Anti-viral (replication) effects

Question 31

What do interleukins do?

Answer 31

Messaging between leukocytes

Question 32

What do chemokines do?

Answer 32

Chemotaxis and movement

Question 33

What do growth factors do?

Answer 33

all cells of the immune system come from stem cells in the bone marrow, exposure to different growth factors which are a type of cytokine determines what the stem cell becomes

Question 34

What type of pattern do dendritic cells recognise?

Answer 34

PAMP's

Question 35

What do dendritic cells secrete once activated?

Answer 35

Cytokines

Question 36

Do complements need antibodies?

Answer 36

Yes, induces lysis of cell. Antibodies induce agglutination

Question 37

Where are components of the compliment system mainly produced?

Answer 37

Liver, but also by monocytes and macrophages

Question 38

What does the compliment system have a enzyme cascade system?

Answer 38

So that a small initial response can be rapidly amplified

Question 39

When the initial precursor is activated what happens? Explain the enzyme cascade system

Answer 39

Initial precursor becomes an activated enzyme. This catalyses the cleavage of many molecules along the chain. This causes the molecule to become an enzyme which does the same thing to the next molecule in the cascade.

Question 40

What three pathways of activation of the complement system are there? Explain each briefly

Answer 40

Classical - conformational change in the antibody when it binds leads to complement activation Alternative - direct activation by the surface of pathogens themselves Lectin pathway - lectin is a PRR and binds to carbohydrates only present on pathogens

Question 41

What is the main complement component/opsonin?

Answer 41

C3 (active component C3b)

Question 42

What happens when C3 is activated?

Answer 42

The membrane attack complex (MAC) is formed

Question 43

What does MAC do?

Answer 43

Lyse cells

Question 44

What do the cleaved products of enzyme precursors do?

Answer 44

They are pro inflammatory mediators that can activate mast cells

Question 45

Three ways complement is controlled?

Answer 45

Components have very short half lives Complement is diluted in body fluids There are specific regulatory proteins which help regulate the activity of complement (e.g. CD59 is expressed by many normal cells to make them resistant to complement mediated lysis)

Question 46

What four functions does complement have?

Answer 46

Lysis, opsonisation, activation of inflammatory response, clearance of immune complexes

Question 47

What causes mast cell degranulation?

Answer 47

Inflammatory fragments binding to receptors on the mast cell

Question 48

What do mast cells secrete? What is the met result of mast cell activation?

Answer 48

Histamine. Vasodilation and increased vascular permeability.

Question 49

What do alarm cytokines do?

Answer 49

Increase vascular permeability

Question 50

What are anaphylatoxins?

Answer 50

Proinflammatory mediators

Question 51

What is the opsonin for monocytes?

Answer 51

Mannan-binding lectin

Question 52

Do natural killer cells have antigen specific receptors?

Answer 52

No

Question 53

What are the two types of cell recognition NK cells have?

Answer 53

Induced self (stress patterns of self proteins) and missing self (when a cell becomes infected their MHC expression is down-regulated)