Host Recognition of Viruses Flashcards
What could a PAMP be?
Envelope protein
Capsid protein
Viral genome (especially dsRNA)
What is an interferon?
Cytokine
What are toll-like receptors?
Inducers of pro-inflammatory responses to PAMPs, only expressed in immune cells.
Secrete cytokines
What do toll-like receptors encode?
Virus coded nucleic acids
What do cytokines do to T-cells?
Tell T-cells whether to differentiate into a cellular or humoral immune repsonse.
What does IL-12 do?
Initiates a cellular adaptive immune response in T-cells
What is RIG1?
A soluble cytoplasmic receptor (RNA helicase).
Composed of CARD domains and a carboxyl terminal helicase domain.
CARD domains are recruitment domains that initiate the signalling pathway
What does RIG-I detect?
Paramyxoviruses
Influenza (-strand)
HepC
In vitro transcribed dsRNA
What is the U7 tract in Influenza A?
Template for the PolyA tail
What is the physiological ligand?
5’ppp required for RIG-I mediated immuno-stimulation, bound by C-terminal domain.
In influenza is forms a distinctive panhandle
how is 5’ppp RNA distinguished from host mRNA
Cellular mRNA is capped
What happens to RIG-I in an uninfected cell?
It is folded in on itself
What is Mda-5?
Same domain order and sequence similarity as RIG-I
What does Mda-5 detect?
Picornaviridae, large dsRNA sequences
Why doesn’t RIG-I use the same mechanism for recognition in picornaviridae?
VpG obscures the 5’-triphosphate
