In the Victora lab I will investigate how immune cells in the intestine decide whether to promote tolerance or incite an inflammatory response. In healthy individuals, the immune cells of the gut can distinguish between infectious invaders and the health-promoting microbes that naturally inhabit the intestine—and encounter dietary proteins without triggering an allergic reaction. In preliminary studies, I determined that these responses may be spatially segregated, with tolerance to orally ingested proteins taking place in lymph nodes near the entryway to the small intestine, where the majority of food is absorbed, while inflammatory responses against infectious parasites and bacteria are mounted farther along the intestine. Now, using methods in cell and molecular biology, genetics, and immunology, combined with a new technique developed in the Victora lab, I will separate the cells that are actively engaged in priming an immune response from those that are teaching tolerance and assess exactly where these cells operate, what genetic programs distinguish the two, and how they produce the correct response in regions where good gut microbes, semi-digested proteins, and pathogenic bacteria might all be present at once. Our findings could lead to novel treatments for disorders characterized by the inappropriate activation of intestinal immunity, including food allergies, celiac disease, or inflammatory bowel disease.