NEW YORK (Reuters Health) - A novel experimental vaccine targeting key immune system cells prevents and reverses "new-onset" diabetes in a mouse model, researchers report.

"Certainly, (this vaccine) will not 'reverse' disease in a person who has had diabetes for more than five years," Dr. Nick Giannoukakis from University of Pittsburgh School of Medicine, Pennsylvania cautioned in comments to Reuters Health.

In the journal Diabetes, Giannoukakis and associates report that a single injection of the vaccine significantly delayed the onset of diabetes in the mice and eight consecutive injections prevented the onset of diabetes altogether.

Similar studies in mice with established hyperglycemia (elevated blood sugar) showed that injection of the vaccine twice weekly for no more than 25 days could reverse new-onset hyperglycemia and maintain normal blood sugar levels after vaccine discontinuation.

The protein bits contained in the vaccine were previously shown to effectively enable human immune system cells called dendritic cells to suppress diabetes.

The vaccine will be tested for safety in volunteers with type 1 diabetes pending the completion of preliminary studies now in progress, Giannoukakis said. Once safety is confirmed, the vaccine's ability to reverse newly diagnosed diabetes and to abrogate the evolution of silent type 1 diabetes into full-blown diabetes will be tested. "This we predict to begin by the end of 2010, early 2011," Giannoukakis said.