Welcome to the Nowosad Laboratory, we study decision making in the immune system. We are interested in antibody-producing B lymphocytes and how their education by the mucosal microenvironment shapes antibody responses. Mucosal surfaces represent barriers and are often inhabited by both friendly and harmful bacteria as well as food and other environmental stimuli. We are specifically fascinated by how B cells can sort through all of this confusion to produce different outcomes depending on whether they encounter friend or foe. Far from ignoring harmless bacteria, B lymphocytes are able to respond in similar ways to infection, just without the accompanying inflammation. We explore this phenomenon by using combinations of classic immunology, mouse genetics and cool imaging techniques to figure out how B cells sense their environment and tip the balance towards tolerance or pathogen clearance.