A Toxoplasma gondii Superantigen: Biological effects and implications for the host-parasite interaction

Superantigens exert their biological effects by activating large families of T cells, based on expression of the variable beta chain of the T-cell receptor. As a result, the reactive cells proliferate, secrete high levels of inflammatory cytokines, and ultimately die or become anergic to further stimulation. It is now becoming clear that the intracellular protozoan Toxoplasma gondii has many of these same superantigenic properties. As discussed here by Eric Denkers, this activity may play a key role in the induction of cell-mediated immunity to the parasite, and may prove to be responsible for much of the pathology associated with the clinical manifestations of toxoplasmosis.