Bacterial infections in the intestine cause diarrheal disease worldwide, affecting people of all ages. These bacteria also trigger inflammatory conditions of the digestive tract such as in Crohn’s disease and ulcerative colitis which can lead to chronic illness and hospitalization. Growing evidence suggests that the innate immune system is critical in regulating the body’s response to early infection, and recent research suggests that dysfunction of this innate response may contribute to Crohn’s disease. A strain of Escherichia coli (E. coli) that attaches to cells on the inner lining of the intestine is a major cause of diarrhea in children, but little is known about the mechanisms by which the immune system recognizes and responds to this type of bacterial infection. Mohammed Khan is investigating how the innate immune system detects E. coli infection and the mechanisms that regulate subsequent inflammatory events in the intestine. Using laboratory-grown human intestinal cells and mouse models, Mohammed hopes to reveal novel mechanisms of regulation of inflammation in host defense. This research may lead to new treatments for infectious and inflammatory diseases of the human intestine.