A new study found that part of the Epstein-Barr virus mimics a protein made in the brain and spinal cord, leading the immune system to mistakenly attack the body’s nerve cells.

Scientists have long suspected — but failed to prove — a link between certain viral infections and the development of multiple sclerosis, a crippling autoimmune disease that affects nearly 1 million Americans. Now, a study led by Stanford Medicine researchers has proved that the Epstein-Barr virus, a common type of herpes virus, triggers multiple sclerosis by priming the immune system to attack the body’s own nervous system.

The study, published Jan. 24 in Nature, shows that approximately 20% to 25% of patients with multiple sclerosis have antibodies in their blood that bind tightly to both a protein from the Epstein-Barr virus, called EBNA1, and a protein made in the brain and spinal cord, called the glial cell adhesion molecule, or GlialCAM.

Part of the EBV protein mimics your own host protein — in this case, ...

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