Table 1.
Key examples of pathogen recognition by nucleic acid-sensing Toll-like receptors
| Receptor | Ligand specificity | Class of pathogen recognized | Examples |
|---|---|---|---|
| TLR3 | dsRNA | dsRNA viruses | Reovirus |
| ssRNA viruses | Respiratory syncytial virus, hepatitis C virus | ||
| DNA viruses | HSV-1, HSV-2, vaccinia virus | ||
| Retroviruses | HIV-1 | ||
| Bacteria | Lactic acid-producing bacteria | ||
| Protozoa | Neospora caninum | ||
| TLR7 and TLR8 | ssRNA and RNA breakdown products | ssRNA viruses | Influenza A virus, SARS-CoV |
| Retroviruses | HIV-1 | ||
| Bacteria | Group B streptococcus, Borrelia burgdorferi | ||
| Fungi | Candida spp. | ||
| Protozoa | Leishmania major | ||
| TLR9 | ssDNA (containing CpG motifs) | DNA viruses | HSV-1, HSV-2, HPV, adenovirus |
| Bacteria | Salmonella enterica subsp. enterica serovar Typhimurium, Mycobacterium tuberculosis | ||
| Fungi | Aspergillus fumigatus, Candida spp. | ||
| Protozoa | Plasmodium falciparum, Leishmania major | ||
| TLR13 (mice) | ssRNA | Bacteria | Staphylococcus aureus, Streptococcus pneumoniae |
| ssRNA viruses | Vesicular stomatitis virus |
ds, double-stranded; HPV, human papillomavirus; HSV, herpes simplex virus; SARS-CoV, severe acute respiratory syndrome coronavirus; ss, single-stranded; TLR, Toll-like receptor.