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DNA Vaccine Could Benefit Brains, Immune Systems of MS Patients: Study

Posted on: Monday, 13 August 2007, 18:15 CDT

By LAUREN LA ROSE

TORONTO (CP) - The cause of multiple sclerosis remains unknown, but a newly developed DNA vaccine may hold the key to producing beneficial changes in the immune systems and brains of those living with the disease, according to a new study.

A research team led by Montreal neurologist and neuroimmunologist Dr. Amit Bar-Or administered the vaccine, BHT-3009, to 30 MS patients during a two-year period. The patients were either living with relapsing-remitting MS, marked both by periods suffering symptoms of the disease or in remission, or secondary progressive MS where symptoms worsen, but periods of remission are a possibility.

The vaccine incorporates the sequence of myelin basic protein (MBP), which is thought to be one of the targets of MS, and DNA is incorporated into the cells in the body, which then starts to make the protein. MBP is a specific substance in myelin, which is responsible for protecting nerve cells in the brain and body.

Researchers found that not only did the vaccine prove safe for use on trial subjects, but produced beneficial antigen-specific immune changes.

"If you think that immune cells are attacking the brain, one way of trying to help is to suppress all immune cells. You'll get the bad guys, but you'll also get a lot of other guys," said Bar-Or, the co-lead author of the study and director of the experimental therapeutics program at the Montreal Neurological Institute.

"The antigen-specific therapy says if we knew which specific T-cells, which particular T-cell receptors are involved in causing the disease, and if we were able to change just them in a very selective way, we would spare the rest of the immune system and have much less in terms of side-effects."

Patients treated with the DNA vaccine had fewer clinical relapses and fewer new brain lesions shown by MRI compared to those given a placebo. The presence or development of lesions are used as a way to measure disease activity in patients, Bar-Or said.

Changes noted by researchers included the reduction in the number of specific cytokines, small proteins produced by cells that trigger inflammation, that produce a type of white blood cell targeting myelin protein.

The study, being published in the October print edition of Archives of Neurology, is being touted as the first human trial of a DNA vaccine for an autoimmune disease.

Bar-Or said while the results are promising, the study is in its early phases. The main purpose was to assess the safety of new therapy.

But based on the findings, a randomized clinical trial involving administering BHT-3009 to approximately 290 patients is underway with hopes that successful treatment of MS sufferers could pave the way for the development of similar vaccines to prevent or treat related diseases such as Type 1 diabetes, lupus and rheumatoid arthritis,researchers concluded.

"Eventually, and this is a goal for farther down the road, we believe that the targets of these diseases may not be identical across patients, and so one would really like to reach the stage where we can take blood from an individual and find out in that individual which are the bad guy cells, and then generate a particular individualized treatment with DNA vaccine," Bar-Or said.

At this stage, the treatment is for established diseases to try to stop the disease process and attempt to prevent new activity from happening, Bar-Or said.

Canadians have one of the highest rates of multiple sclerosis in the world, and it is the most common neurological disease affecting young adults in the country, according to the MS Society of Canada.

Source: Canadian Press

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