Receptor or related structure | Cell type or soluble factor | Examples of known natural microbial ligands |
---|---|---|
CD14 | Myeloid cells and soluble forms | PAMPs from bacterial, fungal, and mycobacterial antigens |
Mannose binding lectin | Soluble factor | Binds to mannosides found on bacteria and fungi; activates complement and opsonin for neutrophils |
C-reactive protein | Soluble protein | Opsonin for Gram-positive bacteria |
LPS-binding protein | Soluble protein | Binds to lipopolysaccharide in Gram-negative bacteria and lipoteichoic acid Gram-positive bacteria |
C'3, alternative complement | Soluble proteins | Polysaccharide capsules of bacteria, fungi |
   MD1 | B cells | Coreceptor for LPS on cell surface of B cells |
   MD2 | Myeloid cells | Coreceptor for LPS on macrophages, neutrophils |
   TLR1 | Myeloid cells | Lipopeptide, lipoteichoic acid, LPS of leptospirosis |
   TLR2 | Myeloid cells | Peptidoglycan, lipopeptide, lipoarabinomannan, fungal cell wall components, LPS of leptospirosis |
   TLR3 | Myeloid cells | Double-stranded viral RNA |
   TLR4 | Myeloid cells | LPS, respiratory syncytial virus proteins |
   TLR5 | Myeloid cells | Flagellin from Gram-positive or Gram-negative bacteria |
   TLR6 | Myeloid cells | Zymosan (fungal constituents) along with TLR2 |
   TLR9 | Dendritric cells, B cells, | Unmethylated CpG motifs in prokaryotic DNA epithelial cells |