Gut bacteria from multiple sclerosis patients modulate human T cells and exacerbate symptoms in mouse models

The gut microbiota regulates T cell functions throughout the body. We hypothesized that intestinal bacteria impact the pathogenesis of multiple sclerosis (MS), an autoimmune disorder of the central nervous system, and thus analyzed the microbiomes of 71 MS patients not undergoing treatment and 71 healthy controls. Although no major shifts in microbial community structure were found, we identified specific bacterial taxa that were significantly associated with MS. Akkermansia muciniphila and Acinetobacter calcoaceticus, both increased in MS patients, induced pro-inflammatory responses in human PBMCs and in mono-colonized mice. In contrast, Parabacteroides distasonis, which was reduced in MS patients, stimulated anti-inflammatory interleukin-10 (IL-10)-expressing human CD4+CD25+ T cells, and IL-10+FoxP3+ regulatory T cells (Tregs) in mice. Finally, microbiota transplants from MS patients into germ-free mice resulted in more severe symptoms of experimental autoimmune encephalomyelitis (EAE...