Polysaccharide A (PSA) from the human intestinal commensal Bacteroides fragilis mediates protection against the experimental autoimmune encephalomyelitis in mice. Here, Wang et al. show that the protective function of PSA is exerted through its action on CD39+regulatory CD4 T cells via Toll-like receptor 2 signalling.
- Yan Wang
- Kiel M. Telesford
- Lloyd H. Kasper
