Certain inflammatory diseases may be prevented by collaborative effects of multiple bacterial strains in the gut

It is well established that immune function is affected by the diverse microbial community within the digestive tract, and Honda's team previously discovered that bacteria belonging to the genus Clostridium act on this particular immune pathway in mice to exert a strong anti-inflammatory effect. “We showed that they were responsible for triggering production of Treg cells in the colon of mice”, says Kenya Honda of the RIKEN Center for Integrative Medical Sciences, “and that oral administration of these strains protected mice against colitis and systemic allergic responses”. “None of the organisms alone were nearly as potent as when they were in consortium”, says Honda. “This suggests that cooperation between the strains is essential to their therapeutic effects”. The collective benefit also appears to pertain to humans; analysis of the gut `microbiome` in healthy patients versus individuals with ulcerative colitis revealed that all 17 strains were present at significantly lower levels in the latter group. “A substantial number of patients don't benefit from existing drugs, which also have considerable adverse effects”, says Honda. “We want to clinically test our hypothesis that reconstituting these bacteria to normal levels in patients may help restore immune tolerance and resolve chronic inflammatory processes”.