L19: Intracellular Immunity

Question 1

Where exactly can intracellular pathogens live inside the cell

Answer 1

Inside vesicles

Inside cytoplasm

Question 2

Which pathogens are intracellular

Answer 2

Virus

Intracellular bacteria

Question 3

Where are intracellular bacteria found inside the cell

Answer 3

In the cytoplasm
Or
In the vesicle

Question 4

What type of cell can bacteria infect

Answer 4

Immune

Non immune

Question 5

Which exact immune cell can bacteria invade

Answer 5

Macrophages

Question 6

What is the advantage of the cell becoming invaded inside macrophages

Answer 6

They are shielded from the complement, antibodies and drugs

Question 7

Which type of T cell kills intracellular bacteria that is inside the vesicles

Answer 7

CD4 TH1 cells

Question 8

Which type of T cell deals with intracellular bacteria that is in the cytoplasm

Answer 8

CD8 T cell

Question 9

What type of cell is a macrophage

Answer 9

Antigen presenting cell

Phagocyte

Question 10

Usually what happens to a pathogen when it is phagocytosed by a macrophage

Answer 10

Pathogen is inside a phagosome
Phagsome fuses with lysosome
This forms a phagolysome
Pathogen is presented as a MHC class 2 complex on the macrophage

Question 11

Which part of the phagocytosis part of the macrophage do vesicle restricted bacteria avoid

Answer 11

Fusing the phagosme with lysosome to form a phagolysome

Question 12

If a bacteria is not Brocken down what does this mean in terms of presenting a MHC complex

Answer 12

MHC class 2 processing stops

Question 13

How do bacteria become present in the cytoplasm if they are in phagosome at the beginning

Answer 13

They break out of the phagosome by cytolysins

Question 14

What class of MHC class does cystolic pathogens present as

Answer 14

MHC class 1

Question 15

If cystolic pathogens escape into the cytoplasm what does this mean in terms of presenting MHC 1 complex

Answer 15

Not presented and stops

Question 16

How does the innate immunity kill intracelluar pathogen

Answer 16

Acidification 
Toxic oxygen derived products
Toxic nitrogen oxides 
Antimicrobial peptides
Enzymes 
Competitors

Question 17

What type of T cell does the killing for vesicle/vacuole restricted pathogen

Answer 17

CD4 T cells because they present as MHC CLASS 2

Question 18

How are TH1 cells activated

Answer 18

By dendritic cells that present MHC class 2

Question 19

When the CD4 TH1 cell is activated what do they do

Answer 19

Recognise the complex of bacterial peptide with MCH class 2 and activate the macrophage

Question 20

What happens to the activated macrophage that has the intracellular pathogen

Answer 20

Increase expression of
MHC class
CD40 
Cd80 Amplification 
Fas expression for apoptosis 
Increase in TNF-alpha for apoptosis 
Reactive oxygen intermediaries
Factors that promote acidification

Question 21

Which T cell is involved in killing cystolic resident bacteria

Answer 21

CD8 T cell as the infected cell is presented with MHC class 1

Question 22

How do CD8 T cells kill

Answer 22

They recognise the MHC class 2 and promote cell death

Question 23

What is the most abundant intracellular infection in humans

Answer 23

Tuberculosis

Question 24

Where exactly in the cell does tb live

Answer 24

Vacuole/vesicles

Question 25

What are the clinical symtoms of TB

Answer 25

``` Breathlessness Chest pain Loss of appetite Coughing up blood Tiredness Persistent cough Loss of weight Night sweats ```

Question 26

How does TB survive inside cell

Answer 26

Inhibit 3 key innate mechanisms of: - reactive oxygen production - reactive NO production - prevent phagolysome formation

Question 27

Which cell does TB infect

Answer 27

Macrophages

Question 28

If TB is a vacuole restricted bacteria which T cell is involved in its killing

Answer 28

CD4 TH1 cells

Question 29

How do CD4 TH1 cells help kill the bacteria

Answer 29

Activate the macrophage

Question 30

What happens when the macrophage is activated

Answer 30

Phagolysosome is more efficient

Question 31

Is the macrophage activation alone enough the kill the TB

Answer 31

NO

Question 32

What happens to the infected macrophages

Answer 32

Have a granuloma forming that can kill macrophages

Question 33

What can cause the spread of bacteria again

Answer 33

If the bacteria leak out the granuloma

Question 34

How do we prevent TB

Answer 34

Vaccination of BCG

Question 35

What happen when the granuloma collapses

Answer 35

Become casuesous ( mass of dead macrophages)

Question 36

What are the factors that increase suspectibility to TB

Answer 36

``` HIV Malnutrition Close living Stress Diabetes Alcohol Immunosuppression ```

Question 37

What type of genetic predisposition is likely to increase susceptibility to TB in patients

Answer 37

CD4 T cell defects | TH1 cytokine or receptor defects