A systems-biology approach to identify Toxoplasma effectors that co-opt host cell transcription and their function in immune system suppression.

Toxoplasma is one of the most successful parasites on earth, causing disease by infecting any nucleated cell of any warm-blooded animal. This broad host range requires the parasites? ability to escape the immune system of different animals. To do so, the parasites secrete an array of ~200 proteins into its host. Some of these effector proteins ensure survival within the infected cell, however, others appear to function outside the infected cell by changing the host immune system in a way that is favourable to the parasite. How the effector proteins function in different cells of different host species and contribute to virulence is largely unknown. We have developed a novel technology that now allows us to identify the function of Toxoplasma effectors in different cells of different species much faster than previously possible. We will use it here to identify the most important effectors that make this parasite so successful.