Resistance to cancer and infectious diseases relies on complex responses in our immune system. Natural killer (NK) cells provide a first line of defence, recognizing and killing infected and tumour cells, while sparing normal cells. NK cells use an intricate system of proteins, found on their surface, to either activate or inhibit their “natural killer” activity. However, the mechanisms by which these proteins induce this action are not completely understood. Dr. Valeria Alcón is studying two cellular proteins (CD72 and CD100) that are involved in the activation of several immune cells to determine how these proteins regulate natural killer cell activity. She is also examining how NK cells interact with other immune system cells to induce immune responses. Her research could explain how to activate natural killer cells, leading to the development of more effective treatments for infectious disease and cancer.