title: Legionella pneumophila mediated activation of dendritic cells involves CD14 and TLR2.
abstract: In this study, we analyzed the activation of bone-marrow derived dendritic cells (BMDCs) from mice lacking the cd14-gene with purified Legionella pneumophila lipopolysaccharide and with viable or formalin-killed L. pneumophila. We found that low concentrations of LPS and doses of L. pneumophila that are relevant to infection are dependent on CD14 to activate BMDCs. Higher concentrations of LPS are able to overcome the lack of CD14 indicating that other receptors areinvolved. We, therefore, included studies using BMDCs from mice lacking functional TLR2 and/or TLR4 molecules. We found that purified L. pneumophila LPS as well as L. pneumophila either viable or formalin-killed are able to activate BMDCs from TLR4-deficient C3H/HeJ mice but fail to activate BMDCs from TLR2-knockout mice. Our data show that not only purified LPS from L. pneumophila but also the microorganism itself stimulate BMDCs via TLR2 and that this stimulation is dependent on CD14 in this mouse model.
authors.affiliation: Interfakultäres Institut für Zellbiologie der Universität Tübingen, Abteilung Immunologie, Tübingen, Germany.
authors.forename: Sibylla
authors.initials: S
authors.lastname: Braedel-Ruoff
authors.forename: Marion
authors.initials: M
authors.lastname: Faigle
authors.forename: Norbert
authors.initials: N
authors.lastname: Hilf
authors.forename: Birgid
authors.initials: B
authors.lastname: Neumeister
authors.forename: Hansjörg
authors.initials: H
authors.lastname: Schild
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000502:physiology; D016207:Cytokines / Q000378:metabolism; D003713:Dendritic Cells / Q000187:drug effects*; D007202:Indicators and Reagents; D018664:Interleukin-12 / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D016952:Legionella pneumophila / Q000737:chemistry* / Q000276:immunology; D018950:Lipopolysaccharide Receptors / Q000235:genetics / Q000502:physiology*; D008070:Lipopolysaccharides / Q000737:chemistry / Q000494:pharmacology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D018345:Mice, Knockout; D011971:Receptors, Immunologic / Q000235:genetics / Q000502:physiology*; D012486:Salmonella typhimurium / Q000737:chemistry; D015398:Signal Transduction / Q000187:drug effects; D051195:Toll-Like Receptor 2
chemical_list: D016207:Cytokines; D007202:Indicators and Reagents; D015850:Interleukin-6; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D011971:Receptors, Immunologic; C493486:Tlr2 protein, mouse; D051195:Toll-Like Receptor 2; D018664:Interleukin-12