Toll-like receptor family (TLRs)

Toll-like receptors (TLRs) are a family of pattern recognition receptors (PRRs) that play a fundamental role in the innate immune system by recognizing pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs) (Bio-Techne, Wikipedia). In humans, the family comprises ten members (TLR1–TLR10) that are expressed on sentinel cells such as macrophages and dendritic cells, as well as on non-immune cells like epithelial and endothelial cells (NIH, Wikipedia). These receptors are localized either on the plasma membrane (TLR1, 2, 4, 5, 6, 10) or within endosomal compartments (TLR3, 7, 8, 9), where they detect a diverse array of microbial components including lipids, proteins, and nucleic acids (NIH, PMC). Upon activation, TLRs initiate signaling cascades primarily through the MyD88 or TRIF adapter proteins, leading to the activation of transcription factors such as NF-κB and IRFs, which drive the production of pro-inflammatory cytokines and type I interferons (Thermo Fisher Scientific, PMC). This signaling is crucial for the initial defense against pathogens and for orchestrating adaptive immune responses (NIH, R&D Systems). Dysregulation of TLR signaling is implicated in various pathologies, including sepsis, autoimmune diseases, and cancer progression (Bio-Techne, DelveInsight). Consequently, TLRs are significant therapeutic targets; agonists like imiquimod and CpG oligodeoxynucleotides are used as vaccine adjuvants and in cancer immunotherapy, while antagonists are under development for treating chronic inflammatory conditions (PMC, MDPI).

Other names

Toll-like receptor familyTLR familyPattern recognition receptorsTLRs

Modulation of innate and adaptive immune responses through the agonism or antagonism of specific Toll-like receptor signaling pathways, primarily involving the MyD88 and TRIF adapter proteins (Thermo Fisher Scientific, PMC).