Innate Immunity

Question 1

Why do we have innate immunity?

Answer 1

Adaptive immune response is too slow to protect us from new pathogens (especially viruses)

Question 2

Which type of immunity (adaptive or innate) provides sterile immunity?

Answer 2

Adaptive

Question 3

Give the sites of microbe entry (7)

Answer 3

Conjunctiva (eyes)
Insect into capillary
Scratch
Anus
Gut infections 
Respiratory tract
Urinogenital tract

Question 4

Give the 7 components of innate immunity

Answer 4

Physical barriers
Chemical barriers
Phagocytes
Inflammation
Cytokines/chemokines
Complement
Natural killer cells

Question 5

What is the purpose of the inflammatory response?

Answer 5

To localise and eliminate injurious agents and to remove damaged tissue components

Question 6

What does the inflammatory response enhance (4)?

Answer 6

Permeability and extravasion, neutrophil recruitment, cell adhesion and clotting

Question 7

What is the inflammatory response triggered by?

Answer 7

The release of pro-inflammatory cytokines and chemokines at the site of infections

Question 8

What are cytokines and chemokines?

Answer 8

Glycoprotein hormones that affect immune response

Question 9

How do cytokines act?

Answer 9

To modify the behaviour of cells in the immune response

Question 10

What are most cytokines

Answer 10

Interleukins

Question 11

How do chemokines act?

Answer 11

As chemotactic factors- creating concentration gradients that attract (or repel) specific cell types to the site of infection

Question 12

What is the effect of IL-1?

Answer 12

Enhances response and induces acute-phase secretion

Question 13

What is the effect of IL-6?

Answer 13

Enhances response and induces acute-phase secretion

Question 14

What is the effect of IL-8/CXCL8?

Answer 14

Chemoattractant for neutrophils

Question 15

What is the effect of IL-12?

Answer 15

Diverts immune response to type 1 pro inflammatory and cytokine secretion

Question 16

What is the effect of TNF-alpha?

Answer 16

Induces changes in vascular endothelium

Question 17

What is the main producer of IL-1?

Answer 17

Macrophages and keratinocytes

Question 18

What is the main producer of IL-6?

Answer 18

Macrophages and dendritic cells

Question 19

What is the main producer of IL-8?

Answer 19

Macrophages and dendritic cells

Question 20

What is the main producer of IL-12?

Answer 20

Macrophages and dendritic cells

Question 21

What is the main producer of TNF-alpha?

Answer 21

Macrophages and dendritic cells

Question 22

What does IL-1 act upon?

Answer 22

Lymphocytes and liver

Question 23

What does IL-6 act upon?

Answer 23

Lymphocytes and liver

Question 24

What does IL-8 act upon?

Answer 24

Phagocytes

Question 25

What does IL-12 act upon?

Answer 25

Naive T cells

Question 26

What does TNF-alpha act upon?

Answer 26

Vascular endothelium

Question 27

How do macrophages recognise microbes?

Answer 27

Phagocytosis receptors that bind to their microbes and components

Question 28

What are the 5 types of receptors found on macrophages?

Answer 28

``` Complement Mannose Lipid Scavenger Dectin-1 ```

Question 29

How do macrophages recognise patterns?

Answer 29

Pathogen-associated molecular patterns (PAMPs)

Question 30

What are PAMPs?

Answer 30

Molecules only present on pathogens that are essential for survival and are invariant structures shared by the entire class of pathogens

Question 31

What is the PAMP on gram negative bacteria?

Answer 31

Lipopolysaccharides in the outer membrane

Question 32

What is a lipopolysaccharide?

Answer 32

Lipid anchor with a complex polysaccharide chain floating off into the outside layer

Question 33

What are the PAMPs (3) on gram positive bacteria?

Answer 33

Peptidoglycan, techoic acid, lipoteichoic acid

Question 34

What does PRR stand for?

Answer 34

Pattern recognition receptors

Question 35

What are PRRs?

Answer 35

Host factors that specifically recognise a particular type of PAMP

Question 36

What are the three classes of PRR?

Answer 36

Extracellular, intracellular and secreted

Question 37

How do secreted PRRs work?

Answer 37

They act to tag circulating pathogens for elimination

Question 38

How do extracellular PRRs work?

Answer 38

They recognise PAMPs outside a cell and trigger a coordinated response to the pathogen

Question 39

How do intracellular PRRs work?

Answer 39

Recognise PAMPs inside a cell and act to coordinate a response to the pathogen

Question 40

How does the interferon system work?

Answer 40

The virus infects cell Cell secretes interferon Interferon binds to any other cells to stop them replicating (and therefore the virus replicating inside of them)

Question 41

What is complement?

Answer 41

A system of secreted proteins made in the liver that recognise PAMPs on the surface of microbes and tag them

Question 42

What are the three ways for complement to kill microbes?

Answer 42

Phagocytosis, opsonised or have holes punched in them

Question 43

What does it mean when a cell is opsonised?

Answer 43

A little coat of complement has stopped pathogens being able to infect cells

Question 44

What are the three ways of activating complement?

Answer 44

- recognition of LPS and other PAMPs - non host glycosylation is recognised by MBP and other lectins to activate lectin pathway - membranes that are recognised as non self activate an alternative pathway

Question 45

How much of WBCs are natural killer cells?

Answer 45

4%

Question 46

What are natural killer cells?

Answer 46

Large granular lymphocytes

Question 47

How do natural killer cells work?

Answer 47

They release cytotoxic molecules called granzymes (proteases) or perforins

Question 48

How do NK cells recognise pathogens

Answer 48

Pathogens don’t have MHC molecules on their membranes

Question 49

What disease is linked to a core defect in complement?

Answer 49

Autoimmune diseases like lupus (...it’s never lupus)

Question 50

What illness is linked to a non-core defect in complement?

Answer 50

Susceptibility for a specific type of pathogen like neisseria

Question 51

What disease is linked to a macrophage deficiency?

Answer 51

Chronic granulomatous disease

Question 52

What is chronic granulomatous disease?

Answer 52

No oxidative burst for bacterial killing

Question 53

What disease is linked to an IRF8 mutation?

Answer 53

Susceptibility of TB

Question 54

What is aicardi-goutieres syndrome associated with

Answer 54

Constitutive production of inflammatory cytokines

Question 55

What happens if you have a lack of interferon-responsiveness?

Answer 55

You get a sensitivity to viral infection