US researchers have developed a vaccine that prevents diabetes in laboratory mice bred to develop the disease. It also halted the disease in mice already showing signs of insulin-dependent diabetes.
The work by scientists at the University of North Carolina Chapel Hill published today in the Journal of Immunology offers great promise if it can be used in treatments for humans. It would mean that newly diagnosed Type I diabetics might be able to avoid daily injections of insulin.
Diabetes is caused when the body's immune system destroys islet beta cells, the pancreatic cells which produce insulin. Without them, too little insulin is produced, causing blood sugar levels to go dangerously high.
The North Carolina team created a vaccine based on "plasmid DNA", a harmless DNA assembly that once injected is capable of expressing two different proteins. These proteins are designed to target specific types of killer T-cells, the immune system cells which cause the damage during diabetes.
The proteins blocked the action of those T-cells which attacked the islet cells, but left the remainder of the immune response intact.
"We gave our mice three injections in three weeks, and the majority of the animals have remained diabetes-free for more than a year," said Dr Roland Tisch, assistant professor of microbiology and immunology at Chapel Hill. "Ideally, human patients might require injection of plasmid DNA vaccines only every year or two."
Much further research will be needed before a vaccine is ready for human trials, but the work is promising.
