A team of scientists have developed a way to rewire the body’s immune system so that it no longer launches an autoimmune response and attacks healthy cells as seen in diseases such as multiple sclerosis (MS). Published in the journal Cell Reports, the discovery offers hope for more effective therapies for autoimmune diseases, which are currently difficult to treat.
When our immune system recognizes a threat in the body, be it bacteria or a virus, it launches an immune response that helps us to contain and fight the infection and get back to optimal health. In the case of autoimmune diseases, these responses go too far and start attacking our own healthy cells. For MS, a disease that affects almost 1 million people in America, the immune system attacks myelin proteins in the fatty coating of nerve cells that facilitate the transmission of signals from our brain to various parts of our body. When this happens, MS sufferers lose control over their muscles, which can affect their speech, vision, sensitivity to touch, and ability to walk.
The researchers first examined white blood cells known as T-cells that coordinate the immune system’s response to perceived threats. In the case of treating MS, these T-cells attack the myelin basic proteins (MBP). The researchers found that by presenting these attacking T-cells with repeated doses of the myelin protein they responded to, they could stop them from identifying the MBP as foreign cells.
The process shares similarities with immunotherapy, which has been used to desensitize people’s immune systems to the triggers of their allergies. When the white blood cells were “retrained” to recognize myelin proteins, they made a dramatic switch from attacking the body to protecting it.
The second stage took a closer look at the T-cells to see how their gene expression changed before and after they had been exposed repeatedly to the MBP. They found the immunotherapy-like treatment triggered a response that turns on genes that silence the immune system. Not reacting to MBP was essentially “learned” by the cells as the lack of response was embedded into their genes. T-cells act like the immune system’s commander, so without getting word from up top to attack all other genes that work to activate the immune system, they stay silent.
“This study has led us to finally understand the underlying basis of immunotherapies which desensitize the immune system,” said gene regulation specialist Professor Peter Cockerill in a statement. "Further longer term clinical trials will be needed to determine whether antigen-specific immunotherapies can indeed deliver lasting benefits. If this is successful, the study published today will be the first study defining the actual mechanisms of how T-cells can be made tolerant to the body’s own proteins in a context that may lead to further advances in the battle to overcome autoimmunity."
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