Organisms that cause disease use various strategies to create infection. Bacteria such as Mycobacterium tuberculosis invade cells in the human immune system. These bacteria manipulate the internal machinery of a host cell to enter and survive inside the cell. A cell contains many different types of molecules that interact in complex ways to control cell behaviours. Michael Hsing is studying these interactions to understand how bacterial invasions occur. He is using a computer method, called the semantic network, to simulate molecular interactions and cellular behaviours during bacterial invasions. The research could enable researchers to predict how cells respond in different situations, potentially leading to development of drugs to prevent and treat bacterial infections.