In opposition to TLR4, which forms homodimer, the transmission of signals from TLR2 initiates after its homodimerization as well as its heterodimerization with either TLR1
or TLR6, and possibly TLR10, providing more capability to recognize more ligands molecules and induce different responses (10,12).
(16) examined nine SNP frequencies in the genes encoding TLR1
, TLR2 (R753Q and A-16934T), TLR4, TLR9, and toll-IL-1 receptor domain-containing adaptor protein in a case/control cohort of 136 adult AD cases and 129 healthy individuals.
Fifteen SNPs of the 7 Toll-like receptor gene (TLR1
,2,3,4,5,6, and 9) were amplified by PCR using specific primers (Table 2).
Some of the genes under the strongest pressure are Toll-like receptor genes TLR1
, TLR6 and TLR10.
(1) Depending on their cellular localization or respective PAMPs they identify, TLRs can be divided into two sub groups such as transmembrane (TLR1
, TLR2, TLR4, TLR5, TLR6, and TLR11) and intracellular (TLR3, TLR7, TLR8, and TLR9).
gingivalis was shown to use both TLR4 and a complex of TLR2 plus TLR1
or TLR6 to induce biological responses, PGE2, prostaglandin E2; IL, interleukin; LPS, lipopolysaccharide; MR.
Mycobacterial lipomannan induces matrix metalloproteinase-9 expression in human macrophagic cells through a Toll-like receptor 1 (TLR1
)/TLR2- and CD14-dependent mechanism.
, TLR2, TLR4, TLR5, and TLR6 were expressed on phagocyte cell surfaces and TLR3, TLR7, TLR8, and TLR9 localized within intracellular vesicles.
Microglia express all TLRs 1-9, while astrocytes predominantly express TLR3, although low-level expression of TLR1
, TLR4, TLR5, and TLR9 has also been detected [89,90].
Genetic variation in TLR1
and susceptibility to trauma-associated sepsis and related outcomes.
In rodent and human atherosclerotic lesions, TLRs, particularly TLR1
, TLR2, and TLR4, play a role in T-lymphocyte activation by recruiting and activating leucocytes, regulating foam cell formation, and controlling antigen presentation [46, 47].
Toll was first identified, almost 20 years ago, when it was found to have an essential role in the fly's immunity to fungal infections  and the first human TLR (TLR1
) to be identified immediately followed .