Open Access
Beneficial effects of Bacteroides fragilis polysaccharides on the immune system
Erin B Troy1,Dennis L Kasper1
Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
DOI: 10.2741/3603 Volume 15 Issue 1, pp.25-34
Published: 01 January 2010
(This article belongs to the Special Issue Modulation of host immune responses by bacterial surface glycan)

Bacterial colonization of the intestine is critical for the normal function of the mammalian immune system. However, the specific molecules produced by commensal bacteria that contribute to the modulation of the host immune system are largely uncharacterized. Polysaccharide A (PSA) produced by the ubiquitous human commensal, Bacteroides fragilis is a model symbiosis factor. PSA is capable of activating T cell-dependent immune responses that can affect both the development and homeostasis of the host immune system. Colonization of previously germ-free mice with B. fragilis alone is sufficient to correct the splenic Th1/Th2 imbalance found in germ-free mice. In addition, PSA can provide protection in animal models of colitis through repression of pro-inflammatory cytokines associated with the Th17 lineage. This review provides an overview of the immunologic properties of PSA including the mechanisms of immune system activation and the resulting immunomodulatory effects.

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Erin B Troy, Dennis L Kasper. Beneficial effects of Bacteroides fragilis polysaccharides on the immune system. Frontiers in Bioscience-Landmark. 2010. 15(1); 25-34.