Micro Flashcards
3 type 1 interferon functions
- Induce antimicrobial state in infected and neighbouring cells
- Modulate innate immune response to promote antigen presentation and NK cells but inhibit proinflammation
- Activate the adaptive immune response
How many genes are there that code for IFN beta and alpha
One gene for IFN b, 13/14 isotypes of IFNa. (ie IFNalpha has a lot of subtypes)
List the 3 types of interferon
Type 1 interferon- alpha and beta, beta is produced by all cells and acts on IFNAR which is present on all tissues. Alpha is produced by plasmocytoid dendritic cells
Type 2 interferon- gamma, produced by immune cells (T and NK) and act on IFNGR
Type 3 interferon- lambda- Signals through receptors IL28R and IL10bR that are mainly present on epithelial surfaces.
Give examples of some ISGs stimulated by interferon binding to receptors
PKR Protein Kinase R: inhibits translation (both viral and host translation)
Mx: inhibits incoming viral genomes (surrounds viral capsids)
ADAR : induces errors during viral replication
Serpine: activates proteases which will chop up viral proteins
Viperin: inhibits viral budding which happens at the end of the viral life cycle
IFITM3: stops virus from leaving endosome
How does Hep C evade IFN system
Produces NS3/4 which chops up MAVS
How does influenza evade IFN system
produces NS1 protein which Binds to RIG-I and so cannot signal MAVS
Also stops mRNA from interferon gene and also ISGs from leaving nucleus
How do Pox viruses evade IFN system
They encode cytokine receptors which mpps up the interferon so that they dont bind to adjacent cells
How does EBOLA evade IFN
Ebola viral RNA is normally detected by RIG-I
VP35 protein from ebola can inhibit RIGI from causing interferon production
If some interferons do get produced and attach to nearby cells, another ebola protein called VP24 can inhibit the signalling pathway between interferon binding and the activation of interferon stimulated genes
