Researchers at the Weizmann Institute of Science, Israel, may have discovered a mechanism by which neurons in the central nervous system (CNS) are protected from injury.

The CNS is an immune-privileged site, meaning that it is not readily accessible to cells of the immune system. This can be beneficial in terms of preventing immune cells from inappropriately attacking the CNS-in fact, some diseases such as multiple sclerosis are believed to be caused by inappropriate attack of neurons by immune cells. But immune-privilege can also be disadvantageous, because immune cells that are necessary for tissue repair cannot gain access to damaged neurons.

Using a model whereby rats with a crushed optic nerve received an intraperitoneal injection of different types of immune T cells, Michal Schwartz and colleagues studied the interaction of the CNS and the immune system. They found that specialized cells called anti-myelin basic protein T cells, collected around the damaged optic nerves and protected them from further deterioration following the initial crush. Thus it appears that autoimmune attack of the CNS is not always detrimental and can be helpful in nerve repair.

The researchers discuss a possible mechanism of action for this neuroprotective effect in the paper and Schwartz comments on the significance of these findings in an accompanying photo story.