TABLE 1.
TLR expression on immune/non-immune cells and their ligands.
| TLRs | TLRs expression | Ligands | Origin of ligands |
| TLR1 | Monocytes, macrophages, B and T cells, DCs, NK, and non-immune cells (fibroblast, astrocytes, epithelial cells, and keratinocytes) | Tri-acyl lipopeptide | Bacteria and mycobacteria Neisseria meningitidis |
| TLR2 | Monocytes, macrophages, DCs, and non-immune cells (fibroblast, astrocytes, epithelial cells, and keratinocytes) | Peptidoglycan and LTA Lipoprotein/lipopeptides A phenol-soluble modulin Glycoinositolphopsholipids Glycolipids Porins Atypical LPS | Gram positive bacteria Pathogens Staphylococcus epidermidis Trypanosoma cruzi Treponema maltophilum Neisseria Leptospira interrogans and Porphyromonas gingivalis |
| TLR3 | DCs, macrophages, mast cells, NK, and non-immune cells (fibroblast, astrocytes, epithelial cells, and keratinocytes) | Double-stranded RNA | Virus |
| TLR4 | Monocytes, macrophages, DCs, and non-immune cells (fibroblast, astrocytes, epithelial cells, and keratinocytes) | LPS Hsp60 | Gram-negative bacteria Chlamydia Pneumoniae |
| TLR5 | Monocytes, macrophages, T cells, DCs, and non-immune cells (fibroblast, astrocytes, epithelial cells, and keratinocytes) | Flagellin | Flagellated bacteria |
| TLR6 | Monocytes, macrophages, B and T cells, DCs, NK, and non-immune cells (fibroblast, astrocytes, epithelial cells, and keratinocytes) | Di-acyl lipopetides | Mycoplasma |
| TLR7 | B cells and plasmacytoid DCs | Single-stranded RNA | Virus |
| TLR8 | Monocytes and myeloid DCs | Single-stranded RNA | Virus |
| TLR9 | B cells and plasmacytoid DCs, GI epithelial cells, and keratinocytes | CpG oligodeoxynucleotides | Bacteria and viruses |
| TLR10 | B cells and plasmacytoid DCs | Not determined | Not determined |
The table shows the expression of the 10 TLRs on immune and non-immune cells, the ligands they recognize and the bacteria associated with them.