A large body of epidemiological evidence indicates that infection with the Epstein-Barr virus (EBV), the causative agent of glandular fever, is essential for the development of multiple sclerosis (MS). EBV is a virus that selectively infects human B cells, which are the white blood cells that produce antibodies. In healthy people the number of EBV-infected B cells is kept under strict control by immune cytotoxic T cells, which are white blood cells that kill abnormal cells such as EBV-infected B cells. We have proposed that people with MS have a genetically determined defect in the ability of their cytotoxic T cells to eliminate EBV-infected B cells and that this leads to the accumulation of EBV-infected B cells in the brain, which then cause the brain to be attacked by the immune system.
In the present project we are therefore studying immunity against EBV in people with MS. We have found that people with MS have reduced T-cell immunity against EBV and suggest that this is the explanation for the recent finding that a substantial number of the B cells in the brains of people with MS are infected with EBV. Understanding the mechanism responsible for this defective T-cell immunity against EBV will open up the possibility of developing new therapies for preventing and treating MS.
Updated: 06 January, 2007