L20: Cytotoxic T Cells And Antiviral Response Flashcards
How are viruses recognised by innate immune cells
Via PAMPs and PRR such as toll like receptors
When toll like receptors recognise the virus what type of cytokine do they release
Type 1 interferons
Name type 1 interferons
IFN-alpha
IFN- beta
Which cell produced TNF-alpha
Monocytes
Dendritic cells
What are type 2 interferons
Interferon gamma
Which gene stimulates the production of interferons
ISG- interferon stimulated gene
What is the role of interferons
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
Which drugs act like interferons
Thiazolide
Which enzyme does interferons activate
Protein kinase R
What does protein kinase R do when it is activated
Phosphorylates an initiation factor of ELF2 alpha
What does ELF2-alpha do when it is initiated
Blocks translation and protein synthesis of the virus
What happens to the number of MHC class 1 in virus
Increases
Which T cell recognises MHC CLASS 1
CD8 T cell
What is cross presentation of antigens
When exogenous pathogens/proteins present as MHC 1
When endogenous proteins present as MHC 2
How to naive T cells become activated and proliferate into CD8 cytotoxic T cell
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
What happens if the virus interferes with the production of MHC CLASS 1
Cd8 T cells cannot recognise the infected cell
When cytotoxic CD8 T cell cannot recognise the infected cell due to low number of MHC class 1 which cell recognises it
NK (natural killer) cells
Which adaptive immune system is NK cell part of
Innate immune cell
What type of cell does NK cells target and kill
Cells with low MCH class 1
Which cells present MHC class 1
All cells apart form RBC
What is ADDC
Antibody dependent cytotoxicity
Describe how ADDC works
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
What happens when ADDC goes wrong
ADEI occurs (Antibody dependent enhancement of infection)
What is ADEI
When non neutralising antiviral proteins facilitate virus entry into host cells leading to increased infectivity of the cell
What receptor does the dengue virus enter through
CD16
How does dengue enter
By ADEI
At what type of infection does ADEI occur with
Second infection when there is non neutralising antibodies due to a new stereotype of infection
