The spleen -- an organ in the abdomen that stores blood -- makes immune cells and hosts the interaction of communications between the immune and nervous systems.

Dr. Mauricio Rosas-Ballina and colleagues at the Feinstein Institute said they discovered specialized immune cells in the spleen called macrophages manufacture tumor necrosis factor, or TNF -- a powerful inflammation-producing molecule.

TNF promotes development of severe sepsis, a systemic infection that kills 225,000 people in the United States each year.

Rosas-Ballina and his colleagues established the route the vagus nerve follows from the base of the brain to the splenic nerve that innervates the spleen. The study showed the vagus nerve communicates with the splenic nerve to suppress TNF production by macrophages in the spleen.

The scientists said their findings might promote the development of new and more effective sepsis treatments that use the central nervous system to control cells of the spleen.

The research appears in the Proceedings of the National Academy of Sciences.