The "good bacteria" that inhabit our guts just got even better. As well as crowding out undesirable or dangerous organisms, they may also release molecules that reduce inflammation and protect against colitis.

Bacteroides fragilis is a common bacterium found in the human gut that produces a molecule called PSA, and mouse studies have suggested that PSA can influence the development of immune cells called T cells.

To investigate further, Dennis Kasper at Harvard Medical School and his colleagues inoculated mice whose immune systems were developing with either PSA-producing or non-producing strains of B. fragalis, and with another common bacterium called Helicobacter hepaticus, which can cause colitis in mice.   Read More...