Symbionts exploit complex signaling to educate the immune system.

ABSTRACT: The mammalian immune system is tolerized to trillions of microbes residing on bodily surfaces and can discriminate between symbionts and pathogens despite their having related microbial structures. Mechanisms of innate immune activation and the subsequent signaling pathways used by symbionts to communicate with the adaptive immune system are poorly understood. Polysaccharide A (PSA) of Bacteroides fragilis is the model symbiotic immunomodulatory molecule. Here we demonstrate that PSA-dependent immunomodulation requires the Toll-like receptor (TLR) 2/1 heterodimer in cooperation with Dectin-1 to initiate signaling by the downstream phosphoinositide 3-kinase (PI3K) pathway, with consequent CREB-dependent transcription of antiinflammatory genes, including antigen presentation and cosig

SUBMITTER: Erturk-Hasdemir D 

PROVIDER: S-EPMC6936714 | biostudies-literature | 2019 Dec

REPOSITORIES: biostudies-literature