title: Symbiont-derived sphingolipids modulate mucosal homeostasis and B cells in teleost fish.
abstract: Symbiotic bacteria and mucosal immunoglobulins have co-evolved for millions of years in vertebrate animals. Symbiotic bacteria products are known to modulate different aspects of the host immune system. We recently reported that Flectobacillus major is a predominant species that lives in the gill and skin mucosal surfaces of rainbow trout (Oncorhynchus mykiss). F. major is known to produce sphingolipids of a unique molecular structure. Here we propose a role for F. major and its sphingolipids in the regulation of B cell populations in rainbow trout, as well as an essential role for sphingolipids in trout mucosal homeostasis. We found that F. major-specific IgT titers are confined to the gill and skin mucus, whereas F. major-specific IgM titers are only detected in serum. Live F. major cells are able to stimulate sustained IgT expression and secretion in gills. F. major sphingolipids modulate the growth of trout total skin and gill symbiotic bacteria. In vivo systemic administration of F. major sphingolipids changes the proportion of IgT+to IgM+B cells in trout HK. These results demonstrate the key role of the symbiont F. major and its sphingolipids in mucosal homeostasis via the modulation of mucosal and systemic Igs and B cells.
authors.affiliation: Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerque, NM, USA.
authors.forename: Ali
authors.initials: A
authors.lastname: Sepahi
authors.affiliation: Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerque, NM, USA.|Fish Innate Immune System Group, Department of Cell Biology and Histology, Faculty of Biology, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, Murcia, Spain.
authors.forename: Héctor
authors.initials: H
authors.lastname: Cordero
authors.affiliation: Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
authors.forename: Howard
authors.initials: H
authors.lastname: Goldfine
authors.affiliation: Fish Innate Immune System Group, Department of Cell Biology and Histology, Faculty of Biology, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, Murcia, Spain.
authors.forename: Maria Ángeles
authors.initials: MÁ
authors.lastname: Esteban
authors.affiliation: Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerque, NM, USA.
authors.forename: Irene
authors.initials: I
authors.lastname: Salinas
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood / Q000378:metabolism; D001402:B-Lymphocytes / Q000276:immunology*; D041964:Cytophagaceae / Q000276:immunology / Q000502:physiology*; D029941:Fish Proteins; D005880:Gills / Q000276:immunology / Q000382:microbiology; D006706:Homeostasis; D007136:Immunoglobulins / Q000097:blood / Q000378:metabolism; D009092:Mucous Membrane / Q000276:immunology* / Q000382:microbiology; D017686:Oncorhynchus mykiss / Q000276:immunology / Q000382:microbiology*; D012867:Skin / Q000276:immunology / Q000382:microbiology; D013107:Sphingolipids / Q000276:immunology*; D013559:Symbiosis
chemical_list: D000907:Antibodies, Bacterial; D029941:Fish Proteins; D007136:Immunoglobulins; D013107:Sphingolipids; C569864:immunoglobulin T, teleost