U.S. researchers say they've discovered a new way to control or terminate potentially harmful immune responses that produce inflammation.

Immune responses defend against invading pathogens and eliminate dangerous tumor cells, for example, but once the threat has been destroyed, the immune responses must end. If left uncontrolled, immune activity can cause autoimmune conditions in which the immune system attacks healthy tissues of the body.

The immune system uses many strategies to shut down immune responses, one of which is signaling cells to die. Now Charles Serhan and colleagues at Harvard University Medical School have demonstrated in mice and humans that dying immune cells express a surface protein that allows them to act as sponges, effectively removing factors that would otherwise promote inflammation.

The scientists say their findings highlight a previously unappreciated role of dying immune cells -- potentially offering a strategy for dampening chronic inflammatory conditions by tricking the immune response to terminate the process.

The report appears in this week's issue of the journal Nature Immunology.

Copyright 2006 by United Press International