T regulatory (Treg) lymphocytes play a central role in quieting the immune response in autoimmune diseases. Because many Treg lymphocytes are produced by the gut immune system, researchers are exploring ways to boost the number of these Treg cells to treat patients with autoimmune diseases.
Some species of bacteria that are normal gut flora in mice increase the number of Treg cells. A Japanese team tested the ability of different human gut bacterial species to induce Treg cells in germ-free mice. They identified 17 Clostridia strains that produced the desired effect; inoculating the germ-free mice with all 17 strains simultaneously produced the largest boost. The function (anti-inflammatory cytokine production), as well as the number, of Tre…