The ultimate aim of the Membrane Trafficking in Immune Cells Group (www.membranetrafficking.com) is to understand the intracellular membrane trafficking cascades by which dendritic cells initiate a naive T cell response. Membrane trafficking is the intracellular transport between organelles by means of membrane fission (the budding of vesicles from organelles) and fusion (the merger of organelles). Immune cells release most of their cytokines into the extracellular environment by membrane trafficking, and this is also the process by which surface membrane receptors reach the plasma membrane and extracellular pathogens are ingested. All these processes are required for the activation of CD4+ helper and CD8+ T cell in lymph nodes. Membrane trafficking is a tightly regulated process encompassing many fundamental questions in cell biology, such as: How are cargo molecules selected for inclusion in trafficking vesicles that bud off from the donor organelles? How do these trafficking vesicles find their cognate target organelles? How is organelar identity achieved and maintained? In addition, the membrane trafficking in immune cells poses specific questions for immunology. How do immune cells recognize and take up antigen? How are specific antigens, such as viruses, bacterial and fungal microbes and cancer cells, differently processed? How do immune cells cope with the membrane trafficking requirements for the secretion of vast amounts of cytokines in the extracellular environment upon encountering a pathogen or an inflammatory environment. All this requires rerouting of the intracellular membrane trafficking pathways that govern secretion of cytokines and chemokines as well as for the display of surface proteins at the plasma membrane. We are especially interested in the role of reactive oxygen species (ROS) in membrane trafficking. Dendritic cells produce such ROS enzymatically by means of NADPH oxidases, but also can encounter high ROS in the extracellular environment, for instance in inflammation or cancer (i.e. due to the Warburg effect). We use a multidisciplinary approach, combining beyond state-of-the-art biochemistry and molecular biology techniques with cell biology on primarily primary immune cells isolated from blood as well as from mouse models. More useful information can be found at the homepage of the Membrane Trafficking in Immune Cells Group (www.membranetrafficking.com).