Immune response to Toxoplasma gondii.

Oral-route infection with Toxoplasma gondii sporozoites or tachyzoites leads to the rapid spread of quick-replicating cytolytic tachyzoites throughout the whole body. Toxoplasma easily crosses the blood-retina, encephalic and placental barriers. The acute phase of this infection lasts for less than around ten days. The parasite causes a very strong type-1 response focused on the interferon-gamma secreted by the T lymphocytes. This immune response limits the tissue extension of the parasite, ensuring the survival of the host, but, paradoxically, also aiding the survival of the parasite by converting it into a bradyzoite, an intracellular quiescent resistant form persisting in the muscle and brain tissues.