Immunology. Therapeutic manipulation of gut flora.

In developed countries as many as two individuals in every thousand suffer from inflammatory bowel disease (ulcerative colitis and Crohn's disease). In his Perspective, Shanahan discusses a new therapeutic approach to treating these conditions in which bacteria normally found in the gut are engineered to produce the anti-inflammatory cytokine interleukin-10 and then are fed as probiotics to mice with these disorders (Steidler et al.).