Thursday, June 24, 2010

immunology 2.0: brain, gut?

The Scientist | In order to progress, should the field of immunology look to other organ systems such as the brain and gut, or should it focus its efforts on all that remains unknown about the immune system itself?

"The major advancements in any field come when branches of science collide," said Kevin Tracey, an immunologist at the Feinstein Institute for Medical Research, one of the researchers asked to write their opinion about the future of immunology for the tenth anniversary issue of Nature Immunology.

Tracey's interests lie in the intersection of neurophysiology and immunology, which took the spotlight after the discovery that action potentials of the vagus nerve regulate the release of cytokines from the spleen and other organs. "That's just the beginning. I think there is going to be a lot of nerves and a lot of circuits that control the immune system," Tracey told The Scientist. If so, future medical devices to control these circuits may act like immune-system pacemakers, Tracey predicted, and when implanted along nerves could treat inflammatory diseases including arthritis, colitis, diabetes, heart disease and arteriosclerosis.

B. Brett Finlay, in contrast, argues that the future of immunology lies in the gut. The mucosal lining of the intestines harbors special lymphoid tissues containing white blood cells, and Finlay, a microbiologist at the University of British Columbia in Vancouver, said he believes a better understanding of the interactions between the immune system, the gut and other mucosal surfaces will push the field of immunology forward.

Knowing how the gut interacts with other mucosal membranes is important because an immune reaction in one of these areas can cause changes in others. "When you realize that [the mucosal surfaces] talk to each other, it has quite significant impacts on how we interpret their actions and reactions to infection," Finlay said.

Indeed, differences in intestinal microbes can have substantial effects on the immune system. Even which company a lab buys their mice from can influence the mice's gut microbiota, which in turn influences their immune system and immune response. "Knowing what we know now, it might explain why one lab finds one thing and another finds another," said Finlay.