
                         Roanoke Times
                 Copyright (c) 1995, Landmark Communications, Inc.

DATE: THURSDAY, November 4, 1993                   TAG: 9311040018
SECTION: NATIONAL/INTERNATIONAL                    PAGE: A9   EDITION: METRO 
SOURCE: Associated Press
DATELINE: NEW YORK                                LENGTH: Medium

DIABETES BLOCKED IN MICE

Scientists have blocked the most severe form of diabetes by heading off a destructive mistake in the immune system of mice, a step that might lead to prevention in people.

Researchers had known that human Type I diabetes occurs when pancreas cells that produce insulin are attacked by disease-fighting cells of the immune system.

Past studies have suggested that a key target of that attack was an enzyme in the pancreas cells called GAD, for glutamic acid decarboxylase.

Now, two studies show that GAD plays the same role in mice, and that injecting mice with it can prevent diabetes.

The studies represent "major progress," commented Steinunn Baekkeskov of the University of California, San Francisco, who identified GAD as a target in human Type I diabetes three years ago. The work opens the door to mouse research that eventually might be used to prevent diabetes in humans, she said.

People with Type I, also known as juvenile diabetes, must take daily insulin injections. About 1.4 million Americans have this form of the disease. Scientists are pursuing several strategies to prevent it by suppressing the immune system attack.

The new work is presented in today's issue of the journal Nature. One study was by Daniel Kaufman and colleagues at the University of California, Los Angeles. The other was by Roland Tisch, Dr. Hugh McDevitt and colleagues at the Stanford University Medical Center.

The researchers said the work suggested that such treatments may be useful one day for people susceptible to developing Type I diabetes. But "there's a long way between now and then," McDevitt said.

Mice genetically prone to developing diabetes were injected with GAD at age 3 weeks, before the attack on the pancreas attack began. All the treated mice at UCLA escaped diabetes, as did most of the Stanford mice.

Kaufman said the injections in his experiment apparently inactivated the immune system's T cells that otherwise would have gone after GAD in pancreas cells. McDevitt said he believed his treatment probably altered the T cell response to a more benign form.

It is not clear why the immune system attacks GAD in some people. Kaufman said that in some cases, the harmful T cells might be provoked by exposure to a germ called coxsackievirus, because the virus bears some structural resemblance to GAD.

by CNB