Dendritic cells are rare immune cells necessary for kick-starting all immune responses. Every tissue in the body is populated by several different populations of dendritic cells, a diversity thought to allow tailored control of an ever-changing multitude of infectious agents by the immune system. Contrary to this possibility, our data suggest that at least some types of dendritic cells are adaptable and can start a variety of immune responses. We will use cellular and molecular approaches to explore how dendritic cells change in response to different infectious agents. Our primary goal will be to identify critical features and pathways that allow the same type of dendritic cell to prime allergic disease rather than other types of inflammatory responses. This study will shed light on the mechanisms driving the diversity of immune responses and provide important information to improve the design of immune interventions and vaccines.