Measles attacks 30 million people and kills one million babies a year worldwide. Prof. Yusuke Yanagi and his coworkers demonstrated that the molecule SLAM (CD150) present on immune cells is a receptor for measles virus. As a small animal model to study how measles virus causes disease, they recently made the mouse possessing the human SLAM gene. Interferons are anti-viral molecules produced by infected cells. Prof. Yanagi’s group is now studying how measles virus counteracts interferons at the molecular level.