title: The Soil BacteriumMethylococcus capsulatusBath Interacts with Human Dendritic Cells to Modulate Immune Function.
abstract: The prevalence of inflammatory bowel disease (IBD) has increased in Western countries during the course of the twentieth century, and is evolving to be a global disease. Recently we showed that a bacterial meal of a non-commensal, non-pathogenic methanotrophic soil bacterium,Methylococcus capsulatusBath prevents experimentally induced colitis in a murine model of IBD. The mechanism behind the effect has this far not been identified. Here, for the first time we show thatM. capsulatus, a soil bacterium adheres specifically to human dendritic cells, influencing DC maturation, cytokine production, and subsequent T cell activation, proliferation and differentiation. We characterize the immune modulatory properties ofM. capsulatusand compare its immunological properties to those of another Gram-negative gammaproteobacterium, the commensalEscherichia coliK12, and the immune modulatory Gram-positive probiotic bacterium,Lactobacillus rhamnosusGGin vitro.M. capsulatusinduces intermediate phenotypic and functional DC maturation. In a mixed lymphocyte reactionM. capsulatus-primed monocyte-derived dendritic cells (MoDCs) enhance T cell expression of CD25, the γ-chain of the high affinity IL-2 receptor, supports cell proliferation, and induce a T cell cytokine profile different from bothE. coliK12 andLactobacillus rhamnosusGG.M. capsulatusBath thus interacts specifically with MoDC, affecting MoDC maturation, cytokine profile, and subsequent MoDC directed T cell polarization.
authors.affiliation: Research and Innovation, Østfold Hospital TrustKalnes, Norway; Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life SciencesAas, Norway.
authors.forename: Stine
authors.initials: S
authors.lastname: Indrelid
authors.affiliation: Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences Aas, Norway.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Kleiveland
authors.affiliation: Research and Innovation, Østfold Hospital Trust Kalnes, Norway.
authors.forename: René
authors.initials: R
authors.lastname: Holst
authors.affiliation: Research and Innovation, Østfold Hospital TrustKalnes, Norway; Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life SciencesAas, Norway.
authors.forename: Morten
authors.initials: M
authors.lastname: Jacobsen
authors.affiliation: Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences Aas, Norway.
authors.forename: Tor
authors.initials: T
authors.lastname: Lea
keywords: DC activation; T cell polarization; dendritic cells (DC); environmental bacteria; immune modulation; immunobiotics; old friends hypothesis; soil bacteria