Discovering human host defence mechanisms at the Toxoplasma gondii vacuole

The protozoan parasite Toxoplasma gondii chronically resides in 30% of humans as infections cannot be cleared. Infection is often asymptomatic, with serious complications and death in immunocompromised and congenitally infected humans. It is unclear how normal immunocompetent individuals control Toxoplasma during acute infection. Multiple unknown unique and overlapping mechanisms of Toxoplasma defence must exist in different human cell types. Host defence acts directly at the membrane between the parasite and the cytoplasm. We have developed an artificial intelligence-driven image analysis pipeline to conduct high-throughput single-cell analysis of these defence mechanisms. We will combine this approach with mechanistic cellular studies and unbiased mass spectrometry approaches. Like this, we will systematically define and characterise the human intracellular host defence machinery targeting Toxoplasma gondii in endothelial cells and macrophages. We will address the following aims: I. Elucidate mechanisms driving endo-lysosome-mediated control of Toxoplasma in endothelial cells. II. Define mechanisms of ubiquitin-dependent host defencetargeting Toxoplasma in macrophages. III. Identify novel cellular networks targeting Toxoplasma employing host defence proteins as tools for discovery-based mass spectrometry. By discovering the compendium of host defence machinery that operates at the human Toxoplasma host defence vacuole in two divergent cell lines, this research directly contributes to human health.