Innate Immune Responses to Toxoplasma gondii in Mice and Humans

Primary infection with Toxoplasma gondii stimulates production of high levels of interleukin12(IL-12) and interferon γ(IFN-γ) by cells of the innate immune system.These two cytokines are central to resistance to T.gondii.Signaling through the Toll-like receptor(TLR) adaptor protein MyD88 is indispensable for activating early innate immune responses.Recent studies have established that TLR11 plays a dominant role in sensing T.gondii.At the same time,TLR11 is represented in humans only by a pseudo gene,and the major question of how innate and adaptive immune responses occurs in the absence of TLR11 remains unanswered.In this article,similarities and differences in sensors and effector molecules that determine host resistance to the parasite in humans and mice are discussed.