[Research progress on Toll-like receptors pathways regulating function of regulatory T cells]

Toll like receptors (TLRs) are pattern recognition receptors and represent immune receptors in innate immunity. They are very conservative in evolution and extremely important for the survival of organisms. TLRs initiate signal transduction through binding of endogenous or exogenous ligands to activate a series of downstream important gene expression and activation. Studies have shown that regulatory T cells (Tregs) play a central role in maintaining peripheral immune tolerance and preventing transplant rejection. Tregs express certain TLRs, including TLR2, TLR4, TLR5, TLR7, TLR8, and TLR9. Activation of TLRs may directly or indirectly affect (mainly activate) Treg proliferation and immunosuppressive functions, and this regulation is closely related to the occurrence of infection, autoimmune disease and cancer. The heat shock proteins as TLRs ligand molecules play important roles in the regulation of Treg. Therefore, understanding regulatory mechanisms of TLR pathways on Tregs is of great significance for new drug development and targeted therapy. This review introduces how TLR-mediated pathways regulate Tregs' immune function.