Biologists pinpoint how common virus triggers multiple sclerosis A connection with Epstein–Barr virus has long been suspected, but the underlying mechanism was unclear until now. By Rachel Fieldhouse

https://www.nature.com/articles/d41586-026-02204-1?utm_source=Live+Audience&utm_campaign=69935b4cfc-nature-briefing-daily-20260716&utm_medium=email&utm_term=0_-33f35e09ea-50432164 T-cell overdrive links virus to MS Epstein-Barr virus (EBV) triggers a particularly strong immune response from a particular type of T cell, which hints at why the virus is implicated in the development of the autoimmune disorder multiple sclerosis (MS). Researchers found that the activity of CD4+ T cells in response to EBV was twice as high in people with MS compared to people without the condition, but responsiveness decreased markedly when CD4+ cells were depleted. A treatment that depletes B cells, the immune cells that EBV infects, also reduced CD4+ response, because the cells had fewer stimuli to respond to.