Mariapia Degli-Esposti is an immunologist whose work has provided seminal insights into the immune system’s response to viruses. She defined cellular and molecular mechanisms that enable pathogen protection whilst limiting immunopathology. Her work revealed novel interactions and immunoregulatory functions of Natural Killer cells, how they limit inflammation and influence the development of autoimmunity. Her studies also addressed the breadth of responses required for effective anti-viral immunity and uncovered the importance of strain-specific antibodies in protecting against viral reactivation and disease. Her work has provided fundamental knowledge into the functioning of the immune system and components that could be harnessed therapeutically.