Polysaccharide A Explained

Polysaccharide A (PSA) is a polysaccharide produced by the Gram-negative bacterium Bacteroides fragilis.[1] B.fragilis produces eight identified distinct capsular polysaccharides, identified by the letters "A" through "H".[2]

PSA interacts with Toll-like receptor 2 (TLR2) on dendritic cells.[3] PSA colonization of B. fragilis in the gut mucosa induces regulatory T cells and suppresses pro-inflammatory T helper 17 cells. PSA has been shown to protect animals from experimental diseases like colitis, asthma, or pulmonary inflammation. Nonetheless, PSA can be pro-inflammatory as well as anti-inflammatory.[4]

PSA has been studied extensively in the spleen and gastrointestinal tract, but PSA uses regulatory T cells to reduce inflammation in the central nervous system.

Notes and References

  1. Sun F, Zhang Q, Chen W . A potential species of next-generation probiotics? The dark and light sides of Bacteroides fragilis in health . . 126 . 108590 . 2019 . 10.1016/j.foodres.2019.108590 . 31732047. 201203450 .
  2. Erturk-Hasdemir D, Ochoa-Repáraz J, Kasper DL, Kasper LH . Exploring the Gut-Brain Axis for the Control of CNS Inflammatory Demyelination: Immunomodulation by Bacteroides fragilis' Polysaccharide A . . 12 . 662807 . 2021 . 10.3389/fimmu.2021.662807 . 8131524 . 34025663 . free .
  3. Rooks MG, Garrett WS . Gut microbiota, metabolites and host immunity . . 16 . 6 . 341-352. 2016 . 10.1038/nri.2016.42 . free . 5541232 . 27231050 .
  4. Alvarez CA, Jones MB, Hambor J, Cobb BA . Characterization of Polysaccharide A Response Reveals Interferon Responsive Gene Signature and Immunomodulatory Marker Expression . . 11 . 556813 . 2020 . 10.3389/fimmu.2020.556813 . 7649347 . 33193325 . free .

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