VAAM-Jahrestagung 2012 18.–21. März in Tübingen

88laboratory conditions the non-cariogenic sweetener xylitol did not revealdecrease of microbial vitality, respiratory activity or EPS-activity.HMP007Flagellin and tcpC are essential factors of the protective effectof E. coli Nissle strain 1917 in DSS- induced colitisS. Menz* 1 , K. Gronbach 1 , P. Adam 2 , A. Wieser 3 , S. Schubert 3 ,U. Dobrindt 4 , T. Ölschläger 5 , I.B. Autenrieth 1 , J.-S. Frick 11 Med. Mikrobiologie & Hygiene, Uni Tübingen, Tübingen, Germany2 Institut für Pathologie, Uni Tübingen, Tübingen, Germany3 Ludwig-Maximilians-Universität München, Max von Pettenkofer-Institut,München, Germany4 Universitätsklinikum Münster, Institut für Hygiene, Münster, Germany5 Julius-Maximilians-Universität Würzburg, Institut für MolekulareInfektionsbiologie, Würzburg, GermanyBackground: The probiotic E. coli Nissle strain 1917 (EcN) is as effectiveas mesalazine in maintenance of remission in ulcerative colitis andshortens the duration of diarrhea in young children. We studied in apreclinical model of acute colitis whether EcN protects from disease andanalysed the bacterial mechanism underlying the anti-inflammatory capacity.Methods: C57BL/6 and TLR5 -/- mice were fed with either EcN orEcNfliC or EcNtcpC and treated with 3, 5% DSS. Body weight anddisease activity index were assessed daily. At the end of the experiment thecolon length and weight was measured and inflammation was determinedby histological analyses of the colon. Furthermore activation andmaturation of lamina propria and mesenteric lymph node dendritic cellsand T cells was analysed.Results: In wild type mice E. coli Nissle protects from DSS induced colitiswhereas the protection is reduced in TLR5 -/- mice. In line with this thefliC mutant strain was less effective in protecting the host from disease ascompared to the EcN wild type strain. However a second bacterial factortcpC also contributes to the protective effect of EcN as the tcpC mutantstrain was not able to protect from disease. Administration of the doublemutant fliCtcpC of EcN evidences this conclusion.Conclusions: EcN ameliorates a DSS induced acute colitis via flagellinand the secreted protein tcpC. However contribution of further bacterialfactors to the anti-inflammatory effect of EcN can not be excluded.HMP008Molecular mechanisms leading to semi-mature murinedendritic cells and their role in intestinal homeostasisA. Steimle* 1 , H.-H. Öz 1 , M. Jucker 2 , J. Geisel 3 , H. Kalbacher 4 , I.B. Autenrieth 1 ,J.-S. Frick 11 University of Tübingen, Institute for Medical Microbiology and Hygiene,Tübingen, Germany2 Hertie-Institut für klinische Hirnforschung ,Abteilung ZellbiologieNeurologischer Erkrankungen , Tübingen, Germany3 University of Tübingen, Institute of Dermatology, Tübingen, Germany4 University of Tübingen, Interfakultäres Institut für Biochemie, Tübingen,GermanyDendritic cells (DCs) can provide different phenotypes. They can displayan immature DC (iDC) phenotype or an activated mature DC (mDC)phenotype. Recently a third phenotype has been discovered, termed semimature(smDCs). These smDCs are able to take up antigen, but not toprocess it and they show reduced expression of T cell activating costimulatorymolecules and a reduced expression of MHC class II. SmDCfail to polarize T cells. Sm BMDCs show reduced cleaving of the invariantchain (Ii) compared to mDCs, a major regulator of the MHC class IItransport to the cell surface, so leading to reduced MHC class II surfaceexpression. The cleaving of Ii is catalyzed by the endosomal proteaseCatS, which is regulated by the endogenous inhibitor Cystatin C. Indeed,mice lacking Cystatin C provide a significant higher susceptibility towardsDSS induced colitis.Therefore we suggest, that semi-maturation plays an important role inmaintaining the intestinal homeostasis and that regulation of Cathepsin Scould be a potential target for the treatment of colitis.HMP009Role of dendritic cell activation as well as Toll-like receptor 2and 4 expression while DSS colitisA. Wittmann* 1 , I.B. Autenrieth 1 , R. Darveau 2 , J.-S. Frick 11 University of Tübingen, Interfacultary Institute for Microbiology andInfection Medicine Tübingen, Tübingen, Germany2 University of Washington, Department of Periodontics, Seattle, United States(DSS) model was employed. Therefore C57BL/6 mice were treated with2.5 % (v/w) DSS for 6 days. DSS treated mice featured and increasedsurface expression of TLR2 and TLR4 on lamina propria dendritic cells(LPDC) compared to healthy mock mice. The role of TLR4 signaling waselucidated precisely by additional administration of E. coli JM83 or E. coliJM83 htrB htrB Pg to mice during DSS challenge. The lipid A structure ofE. coli JM83 htrB htrB Pg features a palmitate instead of laurate and istherefore less endotoxic and induces a weaker TLR4 signaling. Micetreated with DSS and E. coli JM83 administration showed and reducedweight loss, disease activity index and reduced colon shortening comparedto DSS treated and E. coli JM83 htrB htrB Pg administered or DSS onlytreated mice. DSS treatment and administration of E. coli JM83 led as wellto an increased gen expression level of anti-inflammatory genes comparedDSS treatment and E. coli JM83 htrB htrB Pg administration. Theactivation level of LPDC was not important concerning disease severity,since all DSS treated mice independent of bacterial administration featuredhigh surface expression of MHCII, CD40, CD80 and CD86. Of furtherinterest was the distribution of LPDC into subsets, therefore cells wereanalyzed for their surface expression of CD8, CD4, CD11b and CD103.The only difference in subset distribution was the increased percentage ofCD103 + DC in the LP as well as in the mesenteric lymph nodes of micereceiving DSS and E. coli JM83 compared to mice receiving DSS and E.coli JM83 htrB htrB Pg. DSS treated and E. coli JM83 administered miceshowed similar surface expression of TLR2 and reduced surfaceexpression of TLR4 compared to DSS treated and E. coli JM83 htrBhtrB Pg administered miceIncreased appearance of CD103+ DCs and higher amounts of TLR2 andTLR4 are likely to be a counter regulation of the host in order to suppressdeveloping inflammation.HMP010Clonal diversity and geographic signatures of human oralbacterial strains on a world-wide scaleH.-P. Horz 1 , H. Schilling* 1 , O. Kessler 1 , M. Stoneking 1,2 , J. Li 2 , G. Conrads 11 RWTH Aachen Universitätsklinikum, Orale Mikrobiologie und Immunologie,Aachen, Germany2 Max Planck Institute for Evolutionary Anthropology, Department ofEvolutionary Genetics, Leipzig, GermanyObjective: The human microbiome projects seek to describe the bacterialcommunities harboured in the human body. From a medical perspectivethis research has revealed the importance of human-associated microbialcommunities for health or disease. However, viewing the humanmicrobiome from an evolutionary perspective can provide valuableinformation regarding the history of our ancestors (i.e. human migrationpattern). The most prominent and as yet successful example isHelicobacter pylori as its genetic variants could well be correlated withdistinct human populations. The basic drawback of H. pylori relatedstudies however is the requirement of stomach-biopsies which drasticallyreduces the number of samples that can be analyzed. Here we test thehypothesis that the genetic variability of distinct bacterial species in theoral ecosystem may have the similar potential as a chronometer of humanevolution. Methods: To this end saliva samples from ten volunteers eachfrom 12 areas world-wide, representing diverse ethnic groups have beenthe initial focus of this study. Variations in the 16S-23S rDNA internaltranscribed spacer region of Fusobacterium nucleatum and the gdh,(encoding for the glucose-dehydrogenase) and the gtf (encoding for theglucosyl-transferase) of the mitis-streptococci (all of which are typicalpioneers of biofilm formation) have been analyzed by culture-independentmethods. Results: As a result we observed a high intra- and interindividualclonal diversity for all species analyzed. Phylogenetic treereconstruction revealed several clusters shared between two or morecountries but also country-specific lineages. Using the Unifrac significancetest and the P-test showed significant differences between strainpopulations and geographic regions. The degree of those differenceshowever varied among the genes analyzed and the countries included.Conclusions: So far it remains unclear to what extent the differences aredue to divergence and vertical inheritance or rather due to diet and/orgeography influences. However the data indicate that the salivarymicrobiome may hold valuable information for providing new perspectiveson unsolved human migration patterns - an issue of medical, social andanthropological importance.Hosts live normally in symbiosis with their intestinal microbiota due to along co evolution. Somehow this tolerance is abolished in IBD patients,which leads to a strong and long lasting inflammation irregularlyinterrupted by short remission phases.In order to investigate the role of dendritic cells and their TLR2 and TLR4expression while acute phase inflammation the Dextran sodium sulfateBIOspektrum | Tagungsband 2012