Startling Link Between Our Immune and Nervous Systems

Recently, many scientists have found new leads as to how our immune system might actually cause certain nervous system diseases while fighting other pathogens. A few years ago it was discovered that neurons have major histocompatibility complex (MHC) class I molecules on their surface. These proteins, are antigens, which allow our immune system to recognize cells that have been infected by a virus and mark them for destruction. It was thought for many years that neurons were the only cells in the body that did not have the MHC class I molecules.

This discovery prompted testing on mice that lacked this MHC class I molecule. It was discovered that this molecule acts as a “‘molecular brake’ on synaptic plasticity, the ability of brain cells to rewire themselves”. This ability which the MHC class I molecules block is essential to learning and memory functions. These studies also revealed the possibility that these MHC class I molecules may trigger neurodegenerative diseases such as Alzheimer’s and Parkinson’s by causing the immune system to attack brain cells. This same issue is seen in rheumatoid arthritis where the immune system attacks the joints of a person.

Another immune system protein, immunoglobulin-like receptor-B (PirB), was more recently discovered to be expressed by neurons. This protein could lead to the inability to repair neurons damaged in s spinal cord injury or stroke.

These new discoveries unlock a possible cause to disease like Alzheimer’s and Parkinson’s, which are currently incurable. If these discoveries can lead to preventative and curative measures then it would be a great leap for medical science.

However, with a discovery like this the question of whether or not this discovery is a matter of science overstepping its bounds. Some may wonder if because these diseases are caused by our body, whether or not it is our right to stop them.

Society For Neuroscience. "Immune System Research Hold Promise For Alzheimer's, Stroke, And Mental Disorders." ScienceDaily 7 November 2007. 25 April 2010 /releases/2007/11/071106124045.htm>.

-Graham