title: Characterization of the Probiotic Yeast Saccharomyces boulardii in the Healthy Mucosal Immune System.
abstract: The probiotic yeast Saccharomyces boulardii has been shown to ameliorate disease severity in the context of many infectious and inflammatory conditions. However, use of S. boulardii as a prophylactic agent or therapeutic delivery vector would require delivery of S. boulardii to a healthy, uninflamed intestine. In contrast to inflamed mucosal tissue, the diverse microbiota, intact epithelial barrier, and fewer inflammatory immune cells within the healthy intestine may all limit the degree to which S. boulardii contacts and influences the host mucosal immune system. Understanding the nature of these interactions is crucial for application of S. boulardii as a prophylactic agent or therapeutic delivery vehicle. In this study, we explore both intrinsic and immunomodulatory properties of S. boulardii in the healthy mucosal immune system. Genomic sequencing and morphological analysis of S. boulardii reveals changes in cell wall components compared to non-probiotic S. cerevisiae that may partially account for probiotic functions of S. boulardii. Flow cytometry and immunohistochemistry demonstrate limited S. boulardii association with murine Peyer's patches. We also show that although S. boulardii induces a systemic humoral immune response, this response is small in magnitude and not directed against S. boulardii itself. RNA-seq of the draining mesenteric lymph nodes indicates that even repeated administration of S. boulardii induces few transcriptional changes in the healthy intestine. Together these data strongly suggest that interaction between S. boulardii and the mucosal immune system in the healthy intestine is limited, with important implications for future work examining S. boulardii as a prophylactic agent and therapeutic delivery vehicle.
authors.affiliation: Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, United States of America.
authors.forename: Lauren E
authors.initials: LE
authors.lastname: Hudson
authors.affiliation: Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, United States of America.
authors.forename: Courtney D
authors.initials: CD
authors.lastname: McDermott
authors.affiliation: Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, United States of America.
authors.forename: Taryn P
authors.initials: TP
authors.lastname: Stewart
authors.affiliation: Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA, United States of America.
authors.forename: William H
authors.initials: WH
authors.lastname: Hudson
authors.affiliation: Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, Georgia, United States of America.
authors.forename: Daniel
authors.initials: D
authors.lastname: Rios
authors.affiliation: Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, United States of America.
authors.forename: Milo B
authors.initials: MB
authors.lastname: Fasken
authors.affiliation: Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, United States of America.
authors.forename: Anita H
authors.initials: AH
authors.lastname: Corbett
authors.affiliation: Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, United States of America.
authors.forename: Tracey J
authors.initials: TJ
authors.lastname: Lamb
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D005260:Female; D005434:Flow Cytometry; D059014:High-Throughput Nucleotide Sequencing / Q000379:methods; D007107:Immune System / Q000187:drug effects* / Q000276:immunology / Q000382:microbiology; D007124:Immunoenzyme Techniques; D051379:Mice; D008810:Mice, Inbred C57BL; D064307:Microbiota / Q000235:genetics*; D008969:Molecular Sequence Data; D009092:Mucous Membrane / Q000187:drug effects* / Q000276:immunology / Q000382:microbiology; D019936:Probiotics / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012440:Saccharomyces / Q000502:physiology*; D017386:Sequence Homology, Amino Acid
chemical_list: D012333:RNA, Messenger