DNA Vaccine Provides New Hope for Treatment of Multiple Sclerosis

Author:  Falishia Sloan

Institution:  Eastern Virginia Medical School
Date:  August 2007

A study, lead by Amit Bar-Or of the Montreal Neurological Institute, investigating a new DNA vaccine could eventually lead to great advancements in treating multiple sclerosis (MS), one of the most common diseases of the central nervous system. This research, to be published in the October 2007 edition of Archives of Neurology, showed that the vaccine known as BHT-3009 both countered some ill effects of MS and improved patients' lives.

BHT-3009 encodes a full-length human myelin basic protein. Scientists do not yet know the definite cause of MS, but they believe that that the effects of the disease are due to immune cells and antibodies that recognize and attack specific substances, such as myelin basic protein, in the myelin sheaths that protect the axons of nerve cells. Inflammation-triggering cytokines, which are small proteins, are also believed to have a role in MS.

An axon and its myelin sheath can be thought of as an electrical cord with a protective rubber covering, with the rubber providing a safe channel through which an electrical signal can be conducted. When scars or lesions appear on this protective covering after an attack by the immune system, the electrical signal that is to be conducted through the axon is disrupted, causing various neurological dysfunctions. The immune system may also target the axon itself, depleting or destroying various neurological functions.

After the trial, the authors were able to conclude that the BHT-3009 DNA vaccine not only produced favorable results, such as the reduction of the number of CD4+T-cells that specifically target myelin proteins and cause their destruction, but also improved the lives of MS patients. The authors wrote, "BHT-3009 was safe and well tolerated, provided favorable trends on brain MRI and produced beneficial antigen-specific immune changes."

"There were no increases in clinical relapses, disability, drug-associated laboratory abnormalities, adverse events or the number and volume of contrast-enhancing [visible on MRI] lesions on brain MRI with BHT-3009 treatment compared with placebo," the authors explained. "In fact, there was a trend toward a decrease in the number and volume of contrast-enhancing lesions in the brain in patients treated with BHT-3009 compared with placebo."

Such results are promising in the quest for resolving the effects of multiple sclerosis, and, based on this work, a randomized clinical trial with about 290 patients called a phase 2b trial is already in progress. The authors of the study note that this research could lead to great advancements in the treatment of diseases related to MS. "If successful in MS, antigen-specific DNA vaccines can be developed for prevention or treatment of related diseases, such as type 1 diabetes mellitus, systemic lupus erythematosus, rheumatoid arthritis and myasthenia gravis," they wrote.

Written by Falishia Sloan