Table 1.

Toll-Like Receptors and Ligands

TLR	TLR localization	Adaptor molecule	PAMP	DAMP	References
TLR1	Plasma membrane	MyD88/TIRAP	Triacyl lipopeptide soluble factors	—	(117)
TLR2	Plasma membrane	MyD88/TIRAP	Lipoproteins, zymosan, atypical LPS, peptidoglycan, lipoarabinomannan	Hsp60, Hsp70, and glycoprotein 96, HMGB1, hyaluronic acid, matrix metalloproteinase 2, pancreatic adenocarcinoma upregulated factor	(5, 10, 19, 33, 38, 59, 91, 92, 112, 125, 127, 129)
TLR3	Endosome	TRIF	dsRNA	mRNA	(57)
TLR4	Plasma membrane and endosome	MyD88/TIRAP, TRIF/TRAM	LPS, taxol, fusion protein, envelope protein	Hsp60, Hsp70, Hsp72, Hsp22, hyaluronic acid, glycoprotein 96, heparan sulfate, fibrinogen, HMGB1	(3, 15, 25, 55, 56, 88, 89, 92, 100, 101, 106, 111, 121, 129, 130)
TLR5	Plasma membrane	MyD88	Flagellin	HMGB1	(43)
TLR6	Plasma membrane	MyD88/TIRAP	Di-acyl lipopeptides, lipoteichoic acid, β-glucan	Amyloid β and oxidized LDL	(23, 41, 63, 126)
TLR7	Endosome	MyD88	ssRNA, imidazoquinoline, loxoribine, bropirimine	ssRNA miRNA	(1, 44, 48, 73, 83, 131, 142, 143)
TLR8	Endosome	MyD88	ssRNA, midazoquinoline	ssRNA	(45, 83, 131)
TLR9	Endosome	MyD88	CpG-containing DNA, dsDNA, hemozoin	chromatin-IgG complex mtDNA	(11, 20, 36, 66, 67, 76, 81, 96, 141)
TLR10	Plasma membrane	MyD88	Lipopeptides		(42)
TLR11	Endosome	MyD88	Flagellin		(137, 138)
TLR12	Endosome	MyD88	Profilin-like protein		(99)
TLR13	Endosome	MyD88	23s ribosomal RNA		(85)

CpG, cytidine-phosphate-guanosine; DAMP, damage-associated molecular pattern; ds, double-stranded; HMGB1, high-mobility group box 1; Hsp, heat-shock protein; IFN, interferon; LDL, low-density lipoprotein; LPS, lipopolysaccharide; miRNA, microRNA; mtDNA, mitochondrial DNA; MyD88, myeloid differentiation factor 88; PAMP, pathogen-associated molecular pattern; TIRAP, TIR domain-containing adaptor protein; TLR, toll-like receptor; TRAM, Trif-related adaptor molecule; TRIF, TIR domain-containing adaptor inducing IFN-β-mediated transcription factor.