Our body surfaces inhabit a myriad of microbes, our microbiota. These microorganisms live with us in a mutualistic relationship. At our mucosal body surfaces the density and diversity of the microbiota is one of the highest. The Mucosal Immunology group is interested how B cells and their antibodies control our diverse microbiota and to protect from infection by pathogens at mucosal sites. We use human samples and gnotobiotic mouse models that possess a microbiota with defined composition. We pair those models with single cell B cell receptor repertoire analysis and monoclonal antibody testing to functionally define how the humoral immune system contributes to a mutualistic host-microbe relationship. Our long-term goals are: 1) to identify correlates of antibody-mediated protection in mucosal vaccination or infection 2) to improve mucosal vaccination strategies and 3) to define the therapeutic potential of selected monoclonal antibodies to pathogenic bacteria.