L20: Cytotoxic T Cells And Antiviral Response

Question 1

How are viruses recognised by innate immune cells

Answer 1

Via PAMPs and PRR such as toll like receptors

Question 2

When toll like receptors recognise the virus what type of cytokine do they release

Answer 2

Type 1 interferons

Question 3

Name type 1 interferons

Answer 3

IFN-alpha

IFN- beta

Question 4

Which cell produced TNF-alpha

Answer 4

Monocytes

Dendritic cells

Question 5

What are type 2 interferons

Answer 5

Interferon gamma

Question 6

Which gene stimulates the production of interferons

Answer 6

ISG- interferon stimulated gene

Question 7

What is the role of interferons

Answer 7

Inhibit viral protein synthesis
Degrade viral DNA by activating RNAse enzyme
Inhibit viral gene expression
Inhibit virion assembly
Upregulate MHC class 2 so CD8 T cells recognise
Increase P53 activity so virus is killed by apoptosis

Question 8

Which drugs act like interferons

Answer 8

Thiazolide

Question 9

Which enzyme does interferons activate

Answer 9

Protein kinase R

Question 10

What does protein kinase R do when it is activated

Answer 10

Phosphorylates an initiation factor of ELF2 alpha

Question 11

What does ELF2-alpha do when it is initiated

Answer 11

Blocks translation and protein synthesis of the virus

Question 12

What happens to the number of MHC class 1 in virus

Answer 12

Increases

Question 13

Which T cell recognises MHC CLASS 1

Answer 13

CD8 T cell

Question 14

What is cross presentation of antigens

Answer 14

When exogenous pathogens/proteins present as MHC 1

When endogenous proteins present as MHC 2

Question 15

How to naive T cells become activated and proliferate into CD8 cytotoxic T cell

Answer 15

When they recognise MHC class 1 
T cell releases IL-2 to for CD8 T cell proliferation after binding of T cell receptor and MHC CLASS 1

Question 16

What happens if the virus interferes with the production of MHC CLASS 1

Answer 16

Cd8 T cells cannot recognise the infected cell

Question 17

When cytotoxic CD8 T cell cannot recognise the infected cell due to low number of MHC class 1 which cell recognises it

Answer 17

NK (natural killer) cells

Question 18

Which adaptive immune system is NK cell part of

Answer 18

Innate immune cell

Question 19

What type of cell does NK cells target and kill

Answer 19

Cells with low MCH class 1

Question 20

Which cells present MHC class 1

Answer 20

All cells apart form RBC

Question 21

What is ADDC

Answer 21

Antibody dependent cytotoxicity

Question 22

Describe how ADDC works

Answer 22

Antibodies bind to the infected cell
Fc domain of the antibodies is recognised by the NK cell
FC domain of antibodies binds to CD16 receptors on NK cell
NK cell becomes activated and kills the infected cell

Question 23

What happens when ADDC goes wrong

Answer 23

ADEI occurs (Antibody dependent enhancement of infection)

Question 24

What is ADEI

Answer 24

When non neutralising antiviral proteins facilitate virus entry into host cells leading to increased infectivity of the cell

Question 25

What receptor does the dengue virus enter through

Answer 25

CD16

Question 26

How does dengue enter

Answer 26

By ADEI

Question 27

At what type of infection does ADEI occur with

Answer 27

Second infection when there is non neutralising antibodies due to a new stereotype of infection