This interesting study suggests that it may be possible to turn off many forms of autoimmunity by inducing tolerance, in a comparatively simple manner, to the specific fragment of a protein that is causing an immune reaction. There are autoimmunities in which the specific trigger is poorly understood, including the only vaguely cataloged and no doubt highly variable autoimmunities of aging, but many other conditions for which this might be a useful approach.
Autoimmune diseases are caused when the immune system loses its normal focus on fighting infections or disease within and instead begins to attack otherwise healthy cells within the body. In the case of multiple sclerosis (MS), the body attacks proteins in myelin – the fatty insulation-like tissue wrapped around nerves – which causes the nerves to lose control over muscles.
Scientists examined the intricate mechanisms of the T-cells that control the body’s immune system and found that the cells could be ‘re-trained’ to stop them attacking the body’s own cells. In the case of multiple sclerosis, this would prevent the body from attacking the Myelin Basic Protein (MBP) by reprogramming the immune system to recognise the protein as part of itself.
The first stage showed that the immune system can be tricked into recognising MBP by presenting it with repeated doses of a highly soluble fragment of the protein that the white blood cells respond to. By repeatedly injecting the same fragment of MBP, the process whereby the immune system learns to distinguish between the body’s own proteins and those that are foreign can be mimicked. The process, which is a similar type of immunotherapy to that previously used to desensitise people against allergies, showed that the white blood cells that recognise MBP switched from attacking the proteins to actually protecting the body.
The second stage, saw gene regulation specialists probe deep within the white blood cells that react to MBP to show how genes are rewired in response to this form of immunotherapy to fundamentally reprogram the immune system. The repeated exposure to the same protein fragment triggered a response that turns on genes that silence the immune system instead of activating it. These cells then had a memory of this exposure to MBP embedded in the genes to stop them setting off an immune response. When T cells are made tolerant, other genes which function to activate the immune system remain silent.