2. Innate immune responses

Question 1

4 things which make skin a good barrier to infection

Answer 1

1. acidic pH ; 4-5.5
2. desquamation
3. sentinel cells (macrophages + dendritic cells) embedded in membrane
4. sweat contains microbicidal FA to break down bacterial cell walls

Question 2

3 things which make mucous a good barrier to infection

Answer 2

1. thick
2. flora - compete with bacteria
3. ciliated/peristaltic movements

Question 3

2 physiological barriers to infection

Answer 3

1. pH

2. temp >37

Question 4

what protein is produced in tears? what is its funtion?

Answer 4

lysosome - breaks down bacterial cell wall

Question 5

what celll produces defensins ? in what substance?

Answer 5

neutrophils - sweat

Question 6

function of defensins

Answer 6

antimicrobial

Question 7

2 functions of lung surfactacts

Answer 7

1. lubricate surface to prevent infection

2. acts as opsonin for phagocytosis

Question 8

name 2 opsonin proteins

Answer 8

2. C-reactive protein

2. Mannose-binding protein

Question 9

function of lactoferrin and transferrin

Answer 9

Binds iron to microbe - iron is toxic

Question 10

what protein induces fever

Answer 10

IL-1

Question 11

3 functions of complement

Answer 11

1. lysis
2. opsonisation
3. inflammation

Question 12

which 3 cells conduct phagocytosis?

Answer 12

1. macrophage
2. monocyte
3. neutrophil

Question 13

2 functions of dendritic cell

Answer 13

1. produce cytokines - inflammation

2. stimulates adaptive IS

Question 14

when are mast cells activated?

Answer 14

when microbes attach to receptors/Ab

Question 15

2 functions of mast cells

Answer 15

1. inflammation

2. cytokine and proteolytic enzyme release

Question 16

function of NK cells

Answer 16

kill infected host cells

Question 17

3 mechanisms of innate immunity

Answer 17

1. phagocytosis
2. target cell lysis
3. inflammation

Question 18

steps of phagocytosis - innate

Answer 18

1. cell recognisie PAMPS/DAMPS with TLR
2. phagocytotic membrane engulfs microbe
3. phagosome fuses with lysosome - phagolysosome
4. NO, ROS, proteolytic enzymes released to kill microbe

Question 19

5 types of cellular receptors in the innate immune system

Answer 19

1. TLR
2. NLR
3. CDS
4. RLR
5. CLR

Question 20

which cellular receptor is endosomal? what does it recnoginise?

Answer 20

TLR - nucleic acids

Question 21

which cellular receptors are on the cell membrane? what do they recognise?

Answer 21

TLR = bacterial cell wall lipid 
CLR = microbial polysaccharide wall

Question 22

which 3 receptors are cytosolic (give full names)

Answer 22

1. NOD like receptor
2. Rig like receptor
3. Cytosolic DNA sensor

Question 23

what do NLR respond to? what do they cause the activation of?

Answer 23

peptidoglycan bacterial cell wall - activate Transcription factor for inflammation

Question 24

Which receptor responds to viral RNA?

Answer 24

RLR

Question 25

which receptor responds to microbial DNA?

Answer 25

CDS

Question 26

describe structure of TLR

Answer 26

1. ligand binding doman with leucine rich motifs | 2. can either be double or single stranded or lipopolysaccharide

Question 27

function of TLR when activated

Answer 27

Cause transcription which causes the increased expression of cytokines which leads to inflammation and the adaptive response

Question 28

what is the role of phagocytosis in the adaptive response?

Answer 28

antigen presenting cells

Question 29

which type of cells undergo cell lysis?

Answer 29

NK cells - large granular lymphocytes

Question 30

2 types of cells which undergo cell lysis

Answer 30

1. viral infected host cell | 2. phagocytosed microbe

Question 31

describe steps of cell lysis of a viral infected host cell

Answer 31

1. NK cell detects viral proteins | 2. NK cell delivers enzymes to kill the cell

Question 32

describe steps of cell lysis of phagocytosed microbe

Answer 32

1. macrophage with engulfed microbe releases IL-12 2. NK cells detects IL and attaches to the microbe 3. NK cell releases IFN-y 4. instructs macrophage to kill pathogen

Question 33

describe the inflammation response in the innate response

Answer 33

1. mast cells, dendritic cells and macrophages recognise damaged cell - release cytokines and mediators (histamine and heparin) 2. mediators cause increased permeablity of the blood vessel 3. causes entry of complement proteins into tissues AND entry of leukocytes into tissue 3. leukocytes destroy microbes and induce more inflammation and repair

Question 34

2 signals from innate system which induces the adaptive system

Answer 34

1. recognition of antigens by lymphocytes | 2. cytokines