Table 1.
Interaction of HCV proteins with PRRs
| HCV Proteins | PRRs | Interaction of HCV proteins with PRRs | Escape from innate immune system | Escape from adaptive immune system |
|---|---|---|---|---|
|
Core |
TLR2 |
Induction of TLR2 homotolerance |
Serum derived or recombinant core does not recognize TLR2 |
 |
| |
|
Induction of TLR2 crosstolerance with TLR4 |
Monomeric Core recognize core |
|
| |
|
TLR1 or TLR6 are used as coreceptors with TLR2 |
Net Effect = Delayed Immune Response |
|
|
NS3/4A |
TLR3 |
Block TRIF and Cadif (adapter proteins) in down-stream signaling pathways of TLR3 and RIG-1 respectively |
TLR3 and RIG-1 pathways are not activated until sufficient amount of dsRNA is produced, thus delaying innate immune response |
 |
| |
RIG-1 |
|
|
|
| |
TLR2 |
|
|
|
| |
|
TLR1 or TLR6 are used as coreceptors with TLR2 |
|
|
|
NS5A |
TLR4 |
Increases TLR4 expressions |
Block MyD88 (adapter protein) of TLR4 signaling pathway |
 |
| |
|
|
Also downregulates the expression of NFkB, MD2, CD14 and IRF3 |
|
| |
|
|
Increases secretion of IL6, IFNβ, TGFβ and IL10 |
|
| Suppresses IL12 secretion |