Image source: Karolinska Institutet; photo: Erik Holmgren
The new study shows that when the immune system fights EBV, certain T cells – which normally attack the virus – can also react to a protein in the brain called Anoctamin-2 (ANO2). This phenomenon is called molecular mimicry – immune cells mistaking the body’s own proteins for those of the virus. The researchers found that these cross-reactive T cells are significantly more common in people with MS than in healthy controls. The study builds on previous research showing that misdirected antibodies after EBV infection may play a role.
Immune Response to EBV May Damage the Brain in MS
“Our results provide mechanistic evidence that immune responses to EBV can directly damage the brain in MS. It is a complex neurological disease, and it may be that the molecular mechanisms vary between patients,” says the study’s first author, Olivia Thomas, assistant professor at the Department of Clinical Neuroscience at Karolinska Institutet.
T Cells Linking EBV to MS Symptoms
The study is based on analyses of blood samples from people with MS and compared with healthy controls. The researchers were able to isolate T cells that react to both the EBV protein EBNA1 and ANO2 from people with MS. In addition, experiments in a mouse model showed that these cells can exacerbate MS-like symptoms and cause damage to the brain. According to the researchers, the results may help explain why some people develop MS after an EBV infection while others do not.