Toll-like receptor signaling in parasitic infections.

The essential role played by Toll-like receptors (TLRs) during parasitic infections, as a part of the innate immune response, has gained much attention. TLR-induced signaling pathways can eradicate invading pathogens. However, uncontrolled activation of TLR leads to tissue damage. Therefore, negative regulation of TLRs results in diminished pro-inflammatory cytokine production and limits excessive pathology. This review outlines the interplay between TLR-mediated responses and some parasitic infections that involve both activation and negative regulation of TLRs. Furthermore, the promising role of TLRs in both therapeutic strategies and vaccine development for parasitic infections will be highlighted. Moreover, treatment of other diseases, for example, inflammatory bowel diseases, using parasite-derived TLR ligands has initiated a new era in immunotherapy.