TLR4 in Toxoplasmosis; friends or foe?

Toxoplasma species are obligate intracellular protozoan which are responsible for induction of several forms of Toxoplasmosis in humans. The mechanisms responsible for the progression of the prolonged forms of Toxoplasmosis and associated pathologies are yet to be identified. However, previous studies proposed that immunological and genetic parameters may play important roles in the etiology and complexity of Toxoplasmosis. Pathogen recognition receptors (PRRs) recognize microbial antigens and induce immune responses against parasites, including toxoplasma species. Toll like receptors (TLRs) are PRRs which recognize toxoplasma as a pathogenic parasite and activate immune cells. It has been reported that the TLR4 is a critical innate immune cell receptor in toxoplasma detection and subsequently activates immune responses using either MYD88 or TRIF pathways. This review collates recent information regarding the role of TLR4 and its related signaling molecules with Toxoplasmosis.