The immune system relies on an intricate cell-to-cell communication system. This system can warn cells that a virus has been detected. Signaling proteins called cytokines bind specific receptors on cell surfaces, resulting in those cells performing specific preprogrammed actions inside the cell. Juan Mendoza’s work includes studying every cytokine-related interaction outside and inside of cells. These interactions are important for initiating, transmitting, and acting on these warning signals. Using knowledge about these interactions, he aims to find new ways to improve immunotherapies, either by using small molecules or engineered proteins.