Innate Immunity

Question 1

What are the physical barriers?

Answer 1

Skin - boys temp
PH - stomach
Mucous membranes

Question 2

What are the physiological barriers?

Answer 2

Coughing - expulsion of microorganisms in tract

Question 3

Which cells express MHC I?

Answer 3

All cells except neurones

Question 4

What happens when micro biome is disrupted?

Answer 4

Leaky gut - allows some pathogens to transfer to peritoneum and causes infection

Question 5

What do cytokines do?

Answer 5

Activate host defences
Recruitment of immune cells
Activate tissue resident macrophages

Question 6

What are PAMPs and MAMPs?

Answer 6

PAMPs -pathogen associated molecular pathway
MAMPs - molecular associated molecular pathways
Fairly interchangeable - recognise things like component of cell wall, flagella, specific amino acid humans don’t have, sugars like lipopolysaccharides

Question 7

What are recognised by toll-like receptors?

Answer 7

Macrophages
Neutrophils
Epithelial cells of gut and lungs

Question 8

What are DAMPSs?

Answer 8

Damage associated molecular patterns
Detects factors that should be inside the cell. But are outside the cell due to virus replicating inside cell and bursting cell

Question 9

What recognised DAMPs, MAMPs, PAMPs?

Answer 9

Pattern recognition receptors

Question 10

What are Toll-Like Receptors?

Answer 10

Found at the plasma membrane and in endoscomes/phagosomes
Signal production of cytokines (chemokines, interferons) to stimulate innate cells
TLR3 - recognises viral RNA
Some TLRs have to pair up as thy don’t work on their own

Question 11

What is a membrane attack complex?

Answer 11

Funnel that’s stuck in cell wall of microbe
Holes in walls to allow cytotoxic enzymes into cell to kill it
Made by C5b

Question 12

What does c5a do?

Answer 12

Regulates vasodilation, vascular permeability, contraction of small muscles.
Trigger oxidative bursts in WBCs.
Acts as a chemo attractant.

Question 13

What is c5a convertase?

Answer 13

Cleaves C5 to C5a and C5b

Question 14

What diseases are associated with complement?

Answer 14

RA
OA
Atypical haemolytic uremic syndrome
Dense deposit disease
Age related macular degeneration
Hereditary angioedema
Tumours

Question 15

Describe the steps of netosis?

Answer 15

(Done by neutrophils)
Reactive oxygen species releases nuclear elastase (NE) from granules
NE goes to nucleus, chromatin expanses and is released from the cell to capture bacteria
Take pits out of cell membrane, throw it like a net t trap microbes, then pull them in
NE released from granules to lose the bacteria
Debris of pathogen ether used by APC or the on out of the cell for immune system to clear up
(Like phagocytosis but for neutrophils)

Question 16

What are natural killer cells?

Answer 16

Recognise altered self - kill things
Have granules containing toxic enzymes (perforin, granzyme b) that can kill infected clls
Important for virus infected cell, detection of some cancers

Question 17

How are NKs activated?

Answer 17

When interacting with healthy cells MHC I interacts with inhibitory receptors on NKs and inhibits them- if amount of activity on inhibitory receptor > activating receptor NK inhibited
MHC I missing on tumour cells, viral infections so inhibitory receptors not activated and activating receptors are so NK activated.
Stress induced responses will activate NK cells as more activating receptors interacted with then inhibitory

Question 18

Which chronic diseases raise the inflammatory threshold?

Answer 18

Type II diabetes
Alzheimer’s disease
Crohn’s disease
Hepatitis and liver cancer
CVD