[BME Colloquium] Structural identification and immunomodulatory actions of novel symbiotic factors from commensal gut microbe Bacteroides fragilis
  • Sungwhan F. Oh, Ph.D(Harvard Medical School)
  • SLS Colloquia / Sep 4th, 2014 04:00pm / EB1 E104

Human is indeed a small ecosystem, consisting of the single host and densely populated commensal microbiota. Contribution of these symbionts to the host immunity and health is of considerable interest. However, identity of molecular effectors and mechanisms controlling these processes largely remain to be elucidated. Taking advantage of rapidly developing lipidomic/metabolomic techniques, we have identified two unique types of small molecules, glycosphingolipids (aGCs) and a lipid anchor of Polysaccharide A (PSA) from a major gut commensal Bacteroides fragilis. aGCs modulate CD1d-mediated invariant natural killer T cell activation, where PSA lipid anchors regulate TLR2-mediated dendritic cell signaling, respectively.  These results are one of the first examples of species-specific interaction between symbiotic microbes and its host, implying co-evolution of both sides over time.