Table 1.

Different characteristics of TLR genes and TLR proteins in human.

TLR member	TLR coreceptor	TLR family	Gene	TLR genes classification	TLR gene sequences	Gene position	TLR position	TLR active form	Ligands			Adaptors	References
									DAMP (endogenous)	MAMP/PAMP (microbial)	XAMP (synthetic (agonist))
TLR1	TLR2	TLR1	TLR6-TLR1-TLR10	Nonviral	16	4p14	Cell membrane	Heterodimer of TLR1-TLR2	?	Triacyl lipoproteins	Pam3CSK4	BCAP, MAL (TIRAP), MyD88, SCIMP	([23], [71], [123], [117], [88], [42], [50], [6], [8])
TLR2	CD14, CD36, dectin-1, GD1a, integrin β3, RP105, MBL, LBP, vitronectin, TLR1, TLR2, TLR6 TLR10	TLR1	TLR2	Nonviral	24	4q32	Cell membrane	Heterodimer of TLR1-TLR2, homodimer of TLR2-TLR2, heterodimers of TLR2-TLR6 and TLR2-TLR10	Heat shock proteins (HSPs 60, 70, 90), versican, high-mobility group box 1 (HMGB1)	Atypical lipopolysaccharide (LPS), glycoinositolphospholipids, glycolipids, lipoproteins, lipoteichoic acid, zymosan, mannan, peptidoglycan, sporozoite Lipoarabinomannan, porins	Pam2CSK4, Pam3CSK4, Amplivant, Lipoamino acids	BCAP, MAL (TIRAP), MyD88, SCIMP	([23], [71], [123], [25], [88], [86], [124], [139], [130], [42], [50], [6], [7], [121], [8])
TLR3	CD14, Mex3B	TLR3	TLR3	Viral	23	4q35	Endolysosomal plasma membrane and endoplasmic reticulum	Homodimer of TLR3-TLR3	mRNA, siRNA, and tRNA	Viral double-stranded (ds)RNA	Poly(I : C), Poly(A : U)	SARM, SCIMP, TRIF (TICAM1)	([23], [71], [123], [88], [42], [50], [6], [7], [8], [141])
TLR4	Myeloid differentiation factor 2 (MD-2) or LY96, CD14, CD36, LBP, RP105	TLR4	TLR4	Nonviral	22	9q32-33	The cell membrane, endolysosomal plasma membrane, and endoplasmic reticulum	Homodimer of TLR4/MD-2-TLR4/MD-2 Heterodimer of TLR4-TLR6	Heat shock proteins (HSPs 60, 70, 90), amyloid-β peptides, oxidized low-density lipoproteins	LPS, type 1, and P fimbriae	Lipid A and related derivatives, e.g., monophosphoryl lipid A Pyrimido-indole (e.g., UM171), Taxol	BCAP, MAL (TIRAP), MyD88, SARM, SCIMP, TRAM (TICAM2), TRIF (TICAM1)	([23], [187], [71], [123], [88], [188], [139], [130], [42], [50], [6], [7], [148])
TLR5		TLR5	TLR5	Nonviral	23	1q33.3	Cell membrane	Homodimer of TLR5-TLR5	High-mobility group box 1 (HMGB1)	Flagellin	Recombinant flagellin	MyD88, TRIF (TICAM1)	([23], [71], [123], [88], [50], [6], [8])
TLR6	TLR2, CD36, LBP	TLR1	TLR6-TLR1-TLR10	Nonviral	22	4p14	Cell membrane	Heterodimers of TLR2-TLR6 and TLR4-TLR6	Amyloid-β peptides, oxidized low-density lipoproteins, versican	Diacyl lipoproteins, lipoteichoic acid, zymosan	MΦ-activating lipopeptide 2, synthetic diacylated lipoproteins, Pam2CSK4	BCAP, MAL (TIRAP), MyD88, SCIMP	([23], [71], [123], [117], [88], [130], [42], [50], [6], [8])
TLR7	CD14	TLR7	TLR7	Viral	22	Xp22.3	Cell membrane, endolysosomal plasma membrane, and endoplasmic reticulum	Homodimer of TLR7-TLR7	Immune complexes, self RNA	Bacterial and viral (GU-rich) single-stranded (ss) RNA	Imidazoquinoline (such as resiquimod (R848) and imiquimod), thiazoquinoline, oligodeoxynucleotides (ODNs), SM360320, 2-alkoxy-8-hydroxyadenyl derivative, loxoribine, UC-1V150, 3M-012, guanosine analogs	MyD88	([23], [71], [123], [88]; [139], [99], [50], [6], [8], [189])
TLR8		TLR7	TLR8	Viral	23	Xp22	Endolysosomal plasma membrane and endoplasmic reticulum	Homodimer of TLR8-TLR8	Immune complexes, self RNA	Bacterial and viral (GU-rich) single-stranded (ss) RNA	Imidazoquinoline (such as resiquimod (R848) and imiquimod), thiazoquinoline, loxoribine, UC-1V150, 3M-012	MyD88	([23], [71], [123], [88], [139], [50], [6], [189])
TLR9	CD14	TLR7	TLR9	Viral	22	3p21.3	Endolysosomal plasma membrane and endoplasmic reticulum	Homodimer of TLR9-TLR9	Chromatin IgG immune complexes, self DNA, hemozoin	Viral and bacterial unmethylated cytosine phosphate guanine-dideoxy nucleotide (CpG) DNA, DNA : RNA hybrids	A, B, and C classes of CpG-oligodeoxynucleotides (ODNs)	MAL (TIRAP), MyD88, SCIMP	([23], [71], [123], [88], [99], [50]; [6], [7], [189])
TLR10		TLR1	TLR6-TLR1-TLR10 (pseudogene in mice)	Nonviral	17	4p14	Cell membrane, endolysosomal plasma membrane, and endoplasmic reticulum	Heterodimers of TLR1-TLR10 and TLR2-TLR10, homodimer of TLR10-TLR10	?	Diacyl lipoprotein, triacyl lipoprotein, viral glycoproteins, double-stranded (ds) RNA	?	MyD88	([23], [71], [123], [117], [88], [86], [124], [50], [6], [8], [189])