Human Cytomegalovirus Immune Evasion
Human Cytomegalovirus
- known for variety of immune evasion techniques
- congenital infection
- infect many cells: especially respiratory system
- difficult to create vaccine or use immunotherapy
HCMV
Adaptive Immune Response to Viruses
- CD8 T cells
- CD4 T cells
- B cells
- Antibodies
Adaptive Immune Evasion Techniques
MHC presentation
- usually MHC class 1 on every nucleated cell
- Stop MHC class 1 from going to the ER where it is loaded with a peptide
MHC presentation
Latency
- enter non replicative state
- production of IL-10
Latency
Polymorphic
T cells produced to one antigen may not be the same for other strains
Polymorphic
Innate Immune Response
- NK cells
- type one interferons
- other cytokines
- phagocytes
- use of PRRs
Innate
Immune Evasion Techniques
STING Pathway Inhibition
- blocks production of type 1 interferons
- cannot enter anti viral state
STING
NK cells inhibited
- NK cells with many activators/ inhibitors
- without MHC class 1 on a cell, NK not inhibited
- so HCMV produces 'fake' MHC
NK cells
NK cell inhibition example
- activating receptor NKp30 binds to B7-H6 on infected cells
- HCMV with US18 and US20 genes
- downregulate B7-H6 so that NK cells are not acitvated
NK inhibition mechanism