Salmonella bacteria reside in the intestines of animals and can be transmitted to humans via contaminated food or water. These bacteria cause diseases such as typhoid fever and acute gastroenteritis, posing major health problems throughout the world. The body normally produces an immune response to these invading microorganisms. In a process known as phagocytosis, the blood’s immune cells engulf the bacteria, enclose them in specialized internal compartments, and then release destructive enzymes that kill them. However, Salmonella and several other intracellular parasites have evolved methods to subvert this process. By blocking the delivery of the destructive enzymes, these parasites avoid extermination and are able to survive and multiply inside the immune cells. Ultimately, bacteria escape from the cell and spread throughout the body to cause disease. Dr. Leonard Foster is employing advanced proteomic methods and instrumentation to explore and describe what occurs at the molecular level during phagocytosis. This research will lead to a better understanding of the basic operation of this important aspect of immune function. It will also advance knowledge of the molecular mechanisms employed by Salmonella bacteria to prevent the immune cells from delivering the destructive enzymes, potentially leading to better methods of protecting against Salmonella infection.