lecture 9 Flashcards
interferons are released by virus infected cells
IFN-α and IFN-β
what do the inteferons do
induce resistance to viral replication in all cells by inducing what proteins
Mx, 2’-5’ linked adenosine oligomers and kinase PKR
the increase what expression of the surface
MHC class I
they activate what cells
dendritic cells, macrophages and NK cells
what do they induce in order to recruit cells to the area
chemokines
what does 2’-5’ linked adenosine oligomers do
activates endonuclease to degrade viral mRNA
what does PKR do
phosphorylates eIF2 and inhibits protein synthesis
what type are INFalpha and beta
type 1 (early response to infection)
what is the type II interferon
IFNγ
what is IFNγ secreted by
activated T cells and NK cells
natural killer cells are part of what repsonse
Innate
can recognise stressed cells in absence of
Igs and MHC
what do they secrete to kill the cells
granzyme and perforin
MHC class I on normal cells is recognised by inhibitory receptors that inhibit signals from
activating receptors so NK doesnt kill the normal cell
the NK is triggered by signals from activating receptors which causes
secretion of granules causing apoptosis in the target cell
hoe do cytotoxic t cells induce apoptosis
- secrete cytotoxic granules (perforin, granzymes)
- Fas ligand on T cell interacts with Fas on target causing death
cytotoxic t cells also secrete IFNγ causing:
inhibition of viral replication
upregulates MHC I and II expression
increases macrophage phagocytosis
promotes KN killing activity
what is opsonisation
sugar coating pathogens making them more susceptible to phagocytosis
what do antibodies recognise on the virus
heamagglutinin and neuraminidase
what cells does HIV target
CD4 cells, macrophages and DCs
antibodies dont protect againsnt HIV as its
intracellular
patients with higher CTL activity show
slower disease progression
