title: Exopolysaccharides from Cyanobacterium aponinum from the Blue Lagoon in Iceland increase IL-10 secretion by human dendritic cells and their ability to reduce the IL-17+RORγt+/IL-10+FoxP3+ ratio in CD4+ T cells.
abstract: Regular bathing in the Blue Lagoon in Iceland has beneficial effects on psoriasis. Cyanobacterium aponinum is a dominating member of the Blue Lagoon's microbial ecosystem. The aim of the study was to determine whether exopolysaccharides (EPSs) secreted by C. aponinum (EPS-Ca) had immunomodulatory effects in vitro. Human monocyte-derived dendritic cells (DCs) were matured in the absence or presence of EPS-Ca and the effects were determined by measuring the secretion of cytokines by ELISA and the expression of surface molecules by flow cytometry. DCs matured with EPS-Ca at 100 μg/ml secreted higher levels of IL-10 than untreated DCs. Subsequently, DCs matured in the presence or absence of EPS-Ca were co-cultured with allogeneic CD4(+) T cells and their effects on T cell activation analysed by measuring expression of intracellular and surface molecules and cytokine secretion. Supernatant from allogeneic T cells co-cultured with EPS-Ca-exposed DCs had raised levels of IL-10 compared with control. A reduced frequency of IL-17(+)RORγt(+) T cells was observed when co-cultured with EPS-Ca-exposed DCs and a tendency towards increased frequency of FoxP3(+)IL-10(+) T cells, resulting in a lower IL-17(+)RORγt(+)/FoxP3(+)IL-10(+) ratio. The study shows that EPSs secreted by C. aponinum stimulate DCs to produce vast amounts of the immunosuppressive cytokine IL-10. These DCs induce differentiation of allogeneic CD4(+) T cells with an increased Treg but decreased Th17 phenotype. These data suggest that EPSs from C. aponinum may play a role in the beneficial clinical effect on psoriasis following bathing in the Blue Lagoon.
authors.affiliation: Faculty of Pharmaceutical Sciences, University of Iceland, Hagi, Hofsvallagata 53, IS-107 Reykjavik, Iceland; Centre for Rheumatology Research, Landspitali - The National University Hospital of Iceland, Hringbraut, IS-101 Reykjavik, Iceland; Department of Immunology, Landspitali - The National University Hospital of Iceland, Hringbraut, IS-101 Reykjavik, Iceland.
authors.forename: Asa B
authors.initials: AB
authors.lastname: Gudmundsdottir
authors.affiliation: Faculty of Pharmaceutical Sciences, University of Iceland, Hagi, Hofsvallagata 53, IS-107 Reykjavik, Iceland.
authors.forename: Sesselja
authors.initials: S
authors.lastname: Omarsdottir
authors.affiliation: Blue Lagoon Ltd., IS-240 Grindavik, Iceland.
authors.forename: Asa
authors.initials: A
authors.lastname: Brynjolfsdottir
authors.affiliation: Department of Pharmaceutical Chemistry, University of Oslo, 0371 Oslo, Norway.
authors.forename: Berit S
authors.initials: BS
authors.lastname: Paulsen
authors.affiliation: Faculty of Pharmaceutical Sciences, University of Iceland, Hagi, Hofsvallagata 53, IS-107 Reykjavik, Iceland.
authors.forename: Elin S
authors.initials: ES
authors.lastname: Olafsdottir
authors.affiliation: Centre for Rheumatology Research, Landspitali - The National University Hospital of Iceland, Hringbraut, IS-101 Reykjavik, Iceland; Department of Immunology, Landspitali - The National University Hospital of Iceland, Hringbraut, IS-101 Reykjavik, Iceland; Faculty of Medicine, School of Health Sciences, Biomedical Center, University of Iceland, Vatnsmyrarvegur 16, IS-101 Reykjavik, Iceland. Electronic address: jonaf@landspitali.is.
authors.forename: Jona
authors.initials: J
authors.lastname: Freysdottir
mesh_terms: D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D002454:Cell Differentiation / Q000276:immunology; D002478:Cells, Cultured; D018920:Coculture Techniques; D017077:Culture Media, Conditioned / Q000378:metabolism / Q000494:pharmacology; D000458:Cyanobacteria / Q000737:chemistry; D003713:Dendritic Cells / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D007055:Iceland; D007155:Immunologic Factors / Q000494:pharmacology; D016753:Interleukin-10 / Q000276:immunology* / Q000378:metabolism; D020381:Interleukin-17 / Q000276:immunology* / Q000378:metabolism; D008213:Lymphocyte Activation / Q000276:immunology; D057132:Nuclear Receptor Subfamily 1, Group F, Member 3 / Q000276:immunology* / Q000378:metabolism; D011135:Polysaccharides, Bacterial / Q000276:immunology* / Q000494:pharmacology; D014871:Water Microbiology
chemical_list: D017077:Culture Media, Conditioned; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D007155:Immunologic Factors; D020381:Interleukin-17; D057132:Nuclear Receptor Subfamily 1, Group F, Member 3; D011135:Polysaccharides, Bacterial; D016753:Interleukin-10
keywords: Allogeneic T cells; Blue Lagoon; Cyanobacterium aponinum; Dendritic cells; Exopolysaccharides; Immunomodulating effects