Toxoplasma gondii bradyzoites induce transcriptional changes to host cells and prevent IFNγ-mediated cell death

Abstract

Toxoplasma gondii, the causative agent of toxoplasmosis, lies dormant for life and is a reservoir for disease reactivation, causing blindness, encephalitis and congenital birth defects. Acute-stage tachyzoites extensively manipulate their host cell by exporting a repertoire of proteins across the parasitophorous vacuolar membrane (PVM). This interferes with the hosts transcriptional program, allowing for persistence during immune attack. It is unknown how bradyzoites persist and what role host manipulation plays in latency. Here we show that bradyzoite-containing host cells have a unique transcriptional landscape when compared to tachyzoite infection. We demonstrate that many of these changes are dependent parasite protein export. Furthermore, we show that bradyzoite effector proteins protect host cells from IFN{gamma}-mediated cell death, thus highlighting the functional importance of host manipulation. Together, our work provides the first understanding of how Toxoplasma sets up latency to persist in its host.