Virus-fighting cells attacking brain cells (IMAGE) University of Washington Caption A section of brain from a mouse with multiple sclerosis-like disease induced by viral infection. The fluorescently stained image shows a type of killer white blood cell, called CD8+ T cells (colored green), invading the brain and attracting other immune cells (red) that degrade the nerve protein myelin. Myelin forms a sheath around nerves. When the myelin sheath is damaged, the nerve is like a frayed electrical cord that no longer transmits correctly. Credit Goverman Lab, University of Washington Usage Restrictions For use only by news media, educational institutions and museums. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.