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BOB HIRSHON (host):
From stomach to brain…I’m Bob Hirshon and this is Science Update.
In multiple sclerosis, or MS, the immune system attacks the nervous system. But strangely, this attack might be provoked by gut bacteria. Caltech biologist Sarkis Mazmanian and his colleagues experimented with mice that had sterile digestive systems. They tried to induce MS in both the sterile mice and comparable, normal mice.
SARKIS MAZMANIAN (California Institute of Technology):
And what we showed was that animals that were sterile developed very little – if any – symptoms of multiple sclerosis.
HIRSHON:
Then they reintroduced just one kind of bacteria into the sterile mice – a bug previously linked to a type of immune cell involved in MS. Suddenly, the formerly healthy mice developed MS symptoms. While that particular bug can’t live in people, Mazmanian says other gut bacteria might have a similar effect on human MS. I’m Bob Hirshon, for AAAS, the science society.