Understanding the Interactions of the Probiotic Yeast Saccharomyces boulardii with the Mucosal Immune System

The probiotic yeast Saccharomyces boulardii is currently used for the treatment of numerous gastrointestinal disorders, including antibiotic associated diarrhea, inflammatory bowel disease, and recurrences of Clostridium difficile infection. The beneficial effect of this probiotic has been attributed to direct effects on other bacteria, trophic effects on the host intestine, and increases in IgA and anti inflammatory cytokines. However, the exact mechanisms by which S. boulardii exerts its effects on the host immune system are still not fully understood. Better insight into S. boulardii’s interactions with the mucosal immune system will enable a more tailored approach to clinical applications of this probiotic as well as adaptation of this organism for drug delivery in the treatment of gastrointestinal disorders. Here we characterize the interactions of S. boulardii with the murine mucosal immune system. We explore the nature of the increased antibody produced upon oral gavage with S. boulardii and identify the B cell populations contributing to this phenomenon. The data presented here will further elucidate the downstream immunological pathways induced by S. boulardii and provide the foundation for future experiments investigating drug delivery applications of this probiotic.