[Signal transduction pathways mediated by Toll-like receptors and their relations with fungal keratitis]

Toll-like receptors (TLRs) were identified as transmembrane signal transduction proteins in recent years. As a group of pattern recognition receptors (PRRs), TLRs play important roles in the innate immunity by recognizing pathogen-associated molecular patterns (PAMPs). Activated innate immunity subsequently leads to effective adaptive immunity. It, thereby, activities not only innate but ultimately also adaptive immunity. It has been reported that some kinds of TLRs expressed in corneal epithelial cells, stroma cells and endothelial cells. In addition to their recognition function, TLR activation triggers a complex signal transduction cascade that induces the production of inflammatory cytokines and co-stimulatory molecules, thus initiating innate and adaptive immunity. And TLRs play an important role in innate and adaptive immunity of fungal keratitis. In summary, further studies on the regulation of intracellular signaling transduction will contribute significantly to our understanding of immunoregulation of fungal keratitis, eventually provide some way to cure the fungal infection.