Editors have highlighted the following attributes while ensuring the content's credibility:Stem cell-derived blood-brain barrier cells. But thanks to a new UCLA study, researchers have uncovered how some of these viruses breach the brain's defenses—and point toward ways of keeping them out. The team discovered that the invasive strain grips just one or two specific proteins on blood-brain barrier cells, turning those proteins into doorways that let the virus inside. They found that a disease-causing strain of chikungunya was much better at infecting blood-brain barrier cells than a weaker strain that does not cause severe illness. "By learning how they breach the brain's defenses, we can identify their weak points—and that's the first step toward protecting people from the most devastating outcomes."