Table 1.
Nucleic-acid-sensing innate immune receptors.
| Receptor | Ligand | Signaling adaptor | Localization | Cell | Function | Reference |
|---|---|---|---|---|---|---|
| TLR3 | Viral dsRNA, virus/host structured ssRNA, Poly(I:C), ARNAX | TICAM-1 (localization: cytoplasm) | Endosome | Myeloid DC, macrophage, fibroblast, epithelial cell | Antiviral, NK activation, CTL induction, IgA production | (5, 6, 10, 11, 13) |
| TLR7 | Virus/host ssRNA, imidazoquinoline compound | MyD88 (localization: cytoplasm) | Endosome | Plasmacytoid DC, B cell | Antiviral (type-I IFN), Ab production | (2, 7) |
| TLR8 | Virus/host ssRNA, imidazoquinoline compound | MyD88 (localization: cytoplasm) | Endosome | Myeloid DC, monocyte, neutrophil | Antiviral, inflammatory cytokine production | (2, 7) |
| TLR9 | CpG DNA, chromatin/DNA complex | MyD88 (localization: cytoplasm) | Endosome | Plasmacytoid DC, B cell | Antiviral (type-I IFN), Ab production | (2, 7) |
| RIG-I | Viral 5′ppp-dsRNA | MAVS (localization: mitochondrion) | Cytoplasm | Ubiquitous | Antiviral (type-I IFN) inflammatory cytokine production | (2, 3, 8) |
| MDA5 | Viral long dsRNA, Poly(I:C) | MAVS (localization: mitochondrion) | Cytoplasm | Ubiquitous | Antiviral (type-I IFN), inflammatory cytokine production, NK activation | (2, 3, 8) |
| cGAS | dsDNA | STING (localization: endoplasmic reticulum) | Cytoplasm | Ubiquitous | Antiviral (type-I IFN), inflammatory cytokine production, CTL induction | (4, 9) |
| STING | Cyclic dinucleotide | Endoplasmic reticulum | Ubiquitous | Antiviral (type-I IFN), inflammatory cytokine production, CTL induction | (4, 9) |