Officials of the MacArthur Foundation must have had a gut feeling when they awarded Caltech microbiologist Sarkis Mazmanian one of 23 “genius grants,” a half-million dollars over five years to recipients of all stripes, from physicists to novelists.

Mazmanian explores the complex relationship between the immune system and the diverse community of microbes that inhabit the digestive tract. His work could lead to new drugs inspired by beneficial bacteria in the human body, and it has implications for the way in which we see the causes of autism, multiple sclerosis and a host of other conditions and diseases.

“We’re interested in how gut bacteria shape the immune system in a beneficial way,” Mazmanian explained in a recent interview at his office on campus in Pasadena. “This is a growing field, but clearly a departure from mainstream microbiology.”

While other researchers have focused on isolating and analyzing harmful bacteria and viruses that cause disease and death in humans, Mazmanian has spent about a decade looking for the “good guys” -- microbes that live on and within humans and actually render useful services to their hosts, such as digesting tough foodstuffs or reducing inflammation.


“Ten years ago, I realized that most of the organisms we come into contact with in our environment are not bad -- they don’t cause disease,” Mazmanian said. “The great majority of them are quite innocuous. And some of them are actually beneficial. Some of them promote health. And no one was studying these organisms.”

Mazmanian’s work has shown that the immune system’s response to microscopic invaders doesn’t mature fully if the animal doesn’t have any gut microbiota -- making them a key player in the human immune system. His research has linked strains of bacteria to multiple sclerosis, and connected autism to certain types of inflammation (a bodily response triggered by infection).

Mazmanian doesn’t have to continue this particular line of work if he doesn’t want to, though. The ‘genius grant’ doesn’t come with instructions to perform specific research. The MacArthur Foundation looks to support what it refers to as “exceptional merit and promise of continued creative work.”

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