Table 1.

Toll like receptors and their ligands with involved adaptors.

TLR	Localization of immune cell	PAMP	Endogenous ligands
TLR1/2	Cell surface monocyte, macrophage, DC, B cell	Triacyated lipoproteins, peptidoglycan	HSP, HMGB1, β-defensin-3
TLR2	Cell surface monocyte, macrophage, mast cell, B cell	Zymosan, peptidoglycan	HSP, HMGB1, serum amyloid A, surfactant protein A,D, β-defensin-3, antiphospholipid antibody, biglycan
TLR3	Endosomes B cell, T cell, NK cell, DC	dsRNA (viral)	mRNA, tRNA
TLR4	Cell surface/endosomes monocyte, macrophage, DC, mast cell	LPS	HSP, HMGB1, proteoglycans, S100A8, S100A9, S100A12, antiphospholipid antibody, fibronectin, serum amyloid A, oxidized LDL, saturated fatty acids
TLR5	Cell surface monocyte, macrophage, DC,	Flagellin	–
TLR2/6	Cell surface monocyte, macrophage, mast cells, B cell	Diacylated Lipoprotein, Zymosan	–
TLR7	Endosomes monocyte, macrophage, DC, B cell	ssRNA (viral)	ssRNA/IgG complexes, antiphospholipid antibody
TLR8	Endosomes monocyte, macrophage, DC, mast cell	ssRNA (viral)	ssRNA/IgG complexes, antiphospholipid antibody. mircoRNAs
TLR9	Endosomes monocyte, macrophage, DC, B cell, T cell	Unmethylated CpG (viral and bacterial)	Chromatin, IgG complexes, self–DNA including mtDNA

PAMP, pathogen-associated molecular patterns.