Abstract

Apoptosis play a crucial role in the interaction between hosts and parasites. Apoptotic response includes innate and adaptive immunities to restrict intracellular parasite replication and regulatory functions to modulate host immune responses. The obligate intracellular protozoan Toxoplasma gondii extensively modifies apoptosis of its own host cell or of uninfected bystander cells. Upon infection with T. gondii, apoptosis is triggered in T lymphocytes, macrophages and other leukocytes, thereby suppressing immune responses against the parasite. On the other hand, T. gondii inhibits hostcell apoptosis by direct or indirect mechanisms in the infected cells to facilitate parasite survival. The dual activity of T. gondii to both promote and inhibit apoptosis requires tight regulation to stabilize host and parasite interaction and establish toxoplasmosis. Here, molecular mechanisms behind the inhibition or induction of apoptosis by T. gondii infection and their pathogenesis are focused on.