T cells have many jobs, chiefly destroying pathogens. But as people age, a group of T cells called CD8+ cells begin to infiltrate the brain tissue, where they secrete an enzyme that causes inflammation and prevents brain cells from regenerating. Many more CD8+ cells remain in the bloodstream, but their role in ageing wasn't known until now. In the latest study, researchers show that this large population of 'non-infiltrating' T cells actively contributes to cognitive decline. Blocking these effects in the blood might be a more realistic treatment strategy than targeting the cells in the brain, say researchers. 'We don't even have to get into the brain to start treating cognitive decline,' says study co-author Saul Villeda, a neuroscientist at the University of California, San Francisco. 'We can actually block things in blood to have an impact on memory.' The discovery that these cells influence the brain from the outside 'reveals something entirely new', says Paloma Navarro Negredo,...
learn more
