August 2, 2002

Advances

Immune system component found common to both humans and worms

When faced with a bacterial infection, the human body mounts a complex set of reactions. The innate immune system - one of the most basic aspects of the immune response - sounds the alarm and jump starts the body's response to pathogens. Researchers have known that key components of innate immunity are conserved across a variety of animals, and now MGH scientists have shown that these same elements are used by the lowly worm as well. The findings, published in the July 26 issue of Science, suggest that scientists now will be better able to tease out the details of innate immunity across a wide range of species.

"Innate immunity plays a central role in the initial encounter with foreign pathogens and is critical to the host's defense against infection," says co-lead author Dennis Kim, MD, PhD, of the MGH Department of Molecular Biology. "But derangement of the innate immune system is implicated in the pathogenesis of overwhelming infections, as well as in chronic inflammatory diseases. We anticipate that learning about fundamental aspects of the innate immune system may lead to therapies for these conditions."

The research team was seeking common aspects of the immune systems of humans and the C. elegans nematode worm, an animal used in many developmental research studies. In worms that were extra susceptible to pathogens, researchers identified two genetic mutations in a signaling pathway also known to be involved in the innate immune response of humans.

"Because it's the only known component of the immune system common to both C. elegans and humans, this pathway probably represents the most ancient aspect of innate immunity," says principal investigator Frederick Ausubel, PhD. Other study co-authors at the MGH include co-lead author Rhonda Feinbaum, PhD; Genevieve Alloing, PhD; Fred Emerson; Danielle Garsin, PhD; and Man-Wah Tan, PhD.